Getting weird results for some big values

I am using this library and noticed some weird results for some large values. I want to multiply 2 values of max 6144 bits each. Here are my two big number instances I want to multiply together:

{
  bigNumberInstanceA: {
    val: '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',
    neg: false,
    bitlen: 6142
  },
  bigNumberInstanceB: {
    val: '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',
    neg: false,
    bitlen: 6143
  }
}

I have implemented the following function in my smart contract:

    function multiply(BigNumber.instance[2] memory data)
        public
        view
        returns (BigNumber.instance memory)
    {
        return data[0].bn_mul(data[1]);
    }

When calling this function with the mentioned inputs, the result is:

{
    val: '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',
    neg: false,
    bitlen: BigNumber { value: "12281" }
}

Casting the val hex value to BigInt using BigInt(val) gives the value:

6589162891845885612575019946133854740063520802811043717853803045574592257464139801370155694864819502311025730585587379714450022444509839701451537010832711459290336663873265442455715275889705687320688061388706787028315829226828121747550932617639887891374359521545137098704729480301109582594897087889213249373771992712152801239724830920108559084728036514580680135836635540930729794548243871067576085421725929419222689737823277385204297754272577489900410275941196141039053090318785436199834546565283167176460191167585902402842463351141910789344789865373449534827186157483126720684136953055139546207738685742500122468605904098312757083294440300133598952138543470855732112854448933021368213112537322531330308711716817308043265178267760730322294394125708960935661798431453050391561493315381696279277037782869143964815673972357207575929294885505490440945456748848854553649692270942838976680040849007445257006092140293849523452329599727727911423563439421634527849645655262486318035328790625579991044344468228060988309653289487197948209081420590421451127806713815534039046654342981402767740509040005784244413494286324397734927968627046386811957085078739930766419132611342089688042640421198604981876705200687970695218142758141056659101631066836237365724792768198788301369476208452818718201546300306226376415170804056796624360935174024932691864908336957861921239160503307613287584824283125299081010216233173087008546973534571097790340064353801041510058652942709319150781034009394297233187595010576753332598702071875184614399341566500989920179141114217019360097016289783241648167770623255971999307935890912399537141543687057599412973710652307666941311830617778828453373372307132275034065165646668443509439177062478469031416404058792697284640516298149781007253213163788691422010673553639756538294428442733085176240017316789613761134632874628372977601252938811774269668943523134670709403497537148131536354320146668323257372125884342263633754769932698364813032650081122157262885708257406297244123627943618470297965874796707626594924586702471598210006799307394022456759574797023800051132824307253494919165243740307010472916012073567003219104361569287055013636834279166315468071720868796601687600579039415437193460313860979356415124480477904269909060087646994267328198093495757612522018978915121328589206171402112994150727939694945897554493272739447630150089574497875730719701840738527512143492571605457729285332021645702189625043219396409124822943132308075122437398884609157168574298728158614433985819994109031243645245862612647410929969300010696170529989439176381225672310986867871248699861348208208948838850415792567819478216600568572668205428264591941326666122170964836985735404588105644781213923997669053941243245145941575950923731069190229471759600835193014825228946745628342077018300781369545204272228616159945503893549885836723376001910752255593095927269980734971822608893576395447891421104167393584581866365530423149797069124812246520881113579322440750239842367553092412708375316864367356561647167843705039092600594503145487142964057646856244928055767191199971388144949713194562058778663343383233972296598119078065721484939673281051412258473059463594920919061996853584894109102373284991540176131877557912410091180412478245897146384860641865987201962383058658173096501421314333489270196411869385357312155861690975292731595783122596526405203312029193334798400913882778188707428531771699689384186756127461041633106960091592767588592996348198256554954973345778120688985167299811683369317526255178027800602836901478275391058923867815578386036215012489573129145358805444327886490824953277747999569652387724511795949337906027057362708651015537940132999905369575457650422628973935965752982991217340374365591188279

However, the expected result is:

77786989470786096290446181153379605278894675054599450037466273884739744705743495524326810551842132927807523721747568281643253259544666990498353637756387515957723432076069310085718357143217398224018647785718370845026837908145099693498070276840995251638614101791619806030208959033590521185955013440674915897634478613882173411390695524056855621546883291529778063900269996081825588049102140525983639510932190600579603818916929774162435420297441211478664103893686221578729095993851488255464430126637141096065378533514979487725962416739465463907920033131270227034519256767567924540053513233023601632499083416819956517729977110890696128395689985672337756200232470261807324674160392233616016325478672393146364984617748766459626827548648686325801208477507484384632247704634433803416285931787477220387479925504476927190578399439818332424483830458598227194259855391322409390274944181629510859936303649117640988947246865709272109919274946738306324085859404737775164104839340989387106290813589093103269376065120151821994919270068361587544552296980636668942505305677906405275886598385247098791888815543235796258776287122574512324185238226987838332252902332033647507334560394111576769548510727975055101314634248667276548304698643523162061780492280754691734329535357191903585469970887880062201516203126004389455317099724708904875529732431565625458779032135602334234802564369869706563123493389014772688921473203924420268151068964704907645222059137559159890055453240502606110806895556890458499181709940328553496206882251824444175499265717716717877109124196161017155856856717985145990388494735505024196095485930629855499494039866942377160823099663958905683954145172220138590534753716262929918110240069284084657513670826503175706096208664569509482068506324711727872870286708299154170288395970514776494834180784733270115340220561550427964200399837062518292912358530557937931585030398101798331213550354519845151096920880441480260899837568297130085489330655247884380207327915645059034612845923815997721084694341341500784967692100941366347647966598337790828009107876917200612535949893877357657487888652639588256220586048389987840188689025466207689177665698319239951592054044727318086634675902940233838286017845660493005509285555220649160423304462732325477589290900666933131159767012207438294344013748149422132898335200076103063486840661651916981510266739328979816658717261565123981456222991083618934668417253180251266964038408282884782903668324686539176995453886301383715983199921523559578708627952429716805546454914023230565984733367209254010502276171744059026988767763706467614296149087912240223437819709109907296828704175659040717043597144448806147040937049844014598838756672482956370155157266304756666351279499915606815912111069300278485644669100709441168987530830898669388935777355369205804989832228357798320419490910471225685970924581216621922009968381432426752573869059230276226100566078669138270318333514115815419743008225496908712239384387129732146230367638100915785211202638884575239766990129537219120094210864520931571158650564485810916806509881041385577931029723235368086552143324558060599300423350918520075895908343308987756682354256758491946462787700438832919559636547280884879822432512761143914433888977700856823496732083373582837669503954262940927036456599553024805975778682506350985129598370903892645740067116955747765469617045968963754344416958029873867425351263223407149108681723975896481628061415628362304256061081681852485742575710923963022512612569253674605646803104592147821717177074532209316958546345274733429307875315119242545395947848530799484137797920946458126359087011412454331375825543096731255089903981462506607712779479545640538484741423805741577706103023069254720188071908779211555287479095

For most 614x bit integers, the multiplication does give the correct result. Am I overseeing some limitation or configuration? Does anyone have experienced this?

firoorg / solidity-BigNumber

Getting weird results for some big values #8