So as it was previously said, the glass block and glass pane bevahe strangely and glitchy.

-How did it happen?
I don't know.

-When did it start happening?

I saw the glass act like that 2-3 days ago, but I think it's happening since the last update Minecraft had.

P.S. It happens on all Datapacks ranging from the Programmer Art to the Default, it also happens on all Versions, ALL of them, not even the newest ones and it only happens to me, somehow

Here's a picture of how it looks like

And this is how it should look like:

Here's a picture with F3 enabled: