I was playing around on the 1.20 snapshot when I found this seed (below) that had a ruined portal and I noticed that the grass was on the netherrack. I middle-clicked a piece of grass and tried to place it, and it didn't place on the netherrack.
Notes: I'm 99.99% sure it happens on 1.19.4 and under too.
Example Seed: 579358382962016144
Seed on Version: 23w12a
Seed Picture
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