I don't think I've seen anything like this elsewhere in the game (base, or from other mods), but I'm running into a case with this mod where inserters appear to have picked up a charged seed to insert into the agricultural tower, but while the inserter is holding the seed it has gone inert, leaving me with an inserter in the drop position but unable to drop as the tower doesn't want inert seeds.
I'm using the early agricultural tower from the early agriculture mod (I'm doing fulgora before gleba), but would assume (perhaps incorrectly?) the same internal logic is used as in the normal tower.
I frequently leave the game running overnight, and last night set up towers around the island I'm on. I didn't notice any inserters blocked this way before going to bed, but did notice a significant portion (at least 10%, maybe more like 25%) of inserters blocked this morning.
To the best of my knowledge, once an inserter is locked in drop position without there being something on the other end willing to receive what the inserter has in it's hand, the only way to resolve the situation is to destroy the inserter.
I've sorted out a workaround using another (loader) mod but am not sure whether there may be a way to resolve this issue in this mod while retaining the expirable seeds mechanism.