Seems like open plex door + standard armor create some invisible texture issues. I have already saw this issue with open door + transparent blocks but never with opaque blocks. But strangely it happen only on some BP I have downloaded from CC and uploaded on my test server. When I create directly hand-manned entity with standard + door nothing happen.
I didn't merged it with T925 cause it didn't acted like that in previous versions so I presume it's surely unrelated with that bug.