It's not a major issue. As is evident from the logs, the scores are saved—but it shouldn't spit out an error that doesn't matter.
<@WZ1> .unotop
<@Masa-chan> Error loading UNO scores: No JSON object could be decoded
<@Masa-chan> No scores yet
<@WZ1> kek
<@WZ1> .play b 8
<@Masa-chan> We have a winner: WZ1!!! This game took 00:11:46
<@Masa-chan> WZ1 gains 21 points!
<@Masa-chan> Error loading UNO scores: No JSON object could be decoded
<@WZ1> ffs
<@dgw> .unotop
<@Masa-chan> #1 WZ1 (21 points in 1 game (1 won), 0:11:46 wasted)
It's not a major issue. As is evident from the logs, the scores are saved—but it shouldn't spit out an error that doesn't matter.