Shader clipped outside of small area on screen (1.20.2)

Attempting to move the player and some other elements in the inventory; if the player moves out of the original box it is clipped outright
This doesn't seem to have been the case in prior versions (e.g 1.18.2) as I am currently working off another pack intended for that which worked fine
I've messed with the relevant vertex and fragment shader to ensure it doesn't ever set alpha to 0 or discard; this didn't make a difference to the clipping
Looking for any shader that would clip it presumably? But I don't know what that'd be