Tested with GZDoom g4.7.1 and GZDoom g4.8pre-488-g71ce8aa79 - both 64bit
Tested with OpenGL, Vulkan, SoftPoly, and GLES - it happens on all of them
Load this with Doom 2, start MAP01
You'll see two actors using a blueish square model, one of them is partially thru a line portal straight ahead.
Look closely and notice the model on the other side of the portal is mismatched in that it isn't rotated properly.
The other actor isn't touching any portals and is how it's supposed to look.