Seeds pop out from farmland in certain places

I was playing in survival and when I went to plant some seeds for food, I found that they randomly popped out of the ground.

This only seemed to happen when they were in the dark.

Edit: I've found a few odd things:

1. When I break tall grass from the bottom block it drops tall grass.

2. When seeds come out of tall grass it doesn't drop tall grass but seeds with a missing texture.