Any clues on what mod can cause it or how to get rid of it?

Note: When drinking milk, I see everything rendered normally, just for a moment. Then blindness re-applies immediately.

This happens, when you access the Alfheim dimension without properly playing through MythicBotany. (You haven't drunk from the mead of kvasir and therefore, you aren't able to experience Alfheim.)
Anyway: There is a config option (alfheim_locked) to disable this behaviour.

Thanks!
Would be good to inform about it somewhere on the mod description. Unaware admins checking if mod works may consider it is malfunctioning, like me did, LoL.