I'm getting this warn in my client. Don't know what is the problem related.
I found this reference https://github.com/FoundationGames/Sandwichable/issues/57 that maybe could help you understand what is the problem. I just typed the title on google search to find something similar.
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/candlehanging
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/cookies_spidertray
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/guillotine_bed
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/guillotine
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/jack_big
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/jack_group
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/lights_bat
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/lights_pumpkin
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/pumpkinbig
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in halloweenie:item/pumpkingroup
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/cake_chocdrip
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/igloo_bed
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/uprightpiano_black
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/uprightpiano_tan
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/uprightpiano_wood
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/ushanka_black
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/ushanka_cyan
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/ushanka_pink
[16:52:45] [Worker-Main-19/WARN]: Unable to resolve texture reference: #missing in jinglejammin:item/ushanka_red
I'm getting this warn in my client. Don't know what is the problem related. I found this reference https://github.com/FoundationGames/Sandwichable/issues/57 that maybe could help you understand what is the problem. I just typed the title on google search to find something similar.