As per title - if you pick a goblin up in a cage from Supplementaries you can then never release them, they just stay stuck in the cage. Normally you can release mobs from the Supplementaries cage by right clicking.

Same pb here, on cisco fantasy mediaval modpack 1.19.2 forge, supplementaries last version 2.4.20 and goblin trader last version 1.8.0
I can't release the goblin from the cage