Villager can't plant melon and pumpkin seeds, but sometimes look at the farmland and try to plant seeds

The bug

If I give to a villager melon or pumpkin seeds, it won't plant them, but sometimes look at the farmland and try to plant seeds.

Steps to reproduce

1. Use the following command to give the villagers seeds:

   /item replace entity @e[type=minecraft:villager,limit=1,distance=..5] villager.0 with minecraft:melon_seeds 64

   /item replace entity @e[type=minecraft:villager,limit=1,distance=..5] villager.1 with minecraft:pumpkin_seeds 64

2. It is found that villagers sometimes look at the farmland and try to plant seeds.