after selling maximum items villager can take he will not restock

how to reproduce

1.get an villager (for me it was an farmer
2. get him up to lv 3
3.sell melons as much as you can to him
4.wait a couple of minutes
5. after he restocks at higher ammount of items for emerald sell more melons to him

Observed results
Villager will never restock
Expected results
Villager will restock