Melons disappearing in inventory

In survival I collect melons, I craft them in blocs of melons, then I go to the nearest village to sell them. But when I am trading with the farmer I look in my inventory but don't find any melons. I have repeated this operation several times, thinking I made an error. This bug doesn't delete slices of melons, just blocs of melons.
I have to bring the slices in the village and craft them there in blocs, so I've got the time to sell them before they disappear.