Sorry for your trouble :-(
I tried to reproduce this without any luck. I have tried different combinations, including two columns, 1 columns, 2 row , 1 row, different width , height etc.
This is unlikely to do with Pi.. I am fairly sure theres a software bug in the UI code, thats running in the browser which is exposed when you make those changes. I also think this does not impact the controller itself (i.e. ato, lighting etc should work fine), it only breaks the UI. I'll keep trying to reproduce it. Fixing this type of bugs is trivial as long as we can reproduce it.
If its possible, just share the screenshot of the config that breaks the UI, without actually saving it, so that it does not break your UI. I completely understand if its too much ask.