As shown in this error, Smapi fails to load assets from a few mods. I managed to replicate this error with Elle and Hudson mods. Everything works as expected when the game language is set to English, but other languages cause the above error to occur.

I saw that a similar issue was corrected a few days ago, maybe it has something to do with that.

Thanks for all your hard work!

I'll reopen this and double-check that it's fixed for the next release.

The content core is getting refactored in #524, which should fix this. (If it doesn't, feel free to reopen this ticket after that's released.)

Fixed via #524.