i saw a video of someone testing this on the testserver. he had jelly respawn in cleared dungeons after about 3 days. it can take awhile to respawn he said.

if this change woulndt affect dungeons cleared before then they have to address that as that would be pretty harsh in the long run. i cleared alot of mines myself. havent checked any of them yet as i dont use magic much and thats the only thing this is needed for. as of yet.

on the other hand they could just add new ways of getting.

i would just allow broods to spawn as random mobs. this would help this issue already.