Ok duh! I came up with a super simple solution to this problem.
(side note. Forge also won’t let me place mine cart track over hoppers).
Anyways.
Save and quit
quit the main game
relaunch the regular version of the game
open your world place the items you need to place
save and quit and relaunch in forge.
Pain in the butt but it works to at least be able to grow the wart. Till there is a fix
Having the same issue. Using forge 1.13.2 with the quick excavation mod.
Everything else functions fine. Try to plant neather wart on soul sand and nothing. Won’t give me the option to even plant the wart. Tried reloading doesn’t help.