If the extra seeds in the villagers' inventory are not used, their inventory will be full sooner or later. In the vanilla, they only put wheat and beetroot seeds into the composter, they can't put modded seeds into the composter, I hope you can fix this issue. Thanks.

this is a forge feature actually. I assume you are on fabric. in that case that was already on my todo list

Yes i'm using fabric and I also found another bug that the farmers behavior seems doesn't functioning on neoforge version.