Yeah, I got suckered into thinking it might be OGL, because it is such an odd problem. Note that I can no longer duplicate the above second error messages after swapping to the Legacy canvas and back. So, there you have that.
Now when I click "Ignore" it keeps marching along without crashing.
I had the F.Fab layer unchecked and the Render Footprints back unchecked when I saved a project with an older nightly. Launching the newest nightly, these were also unchecked on program launch. Three times in a row, I clicked the above in sequence and on the second click the program crashed (yea, I forgot to copy the text the first time it crashed.
Knowing that swapping between Legacy and OGL does "reset" the grid-bug, I tried the same in Legacy. I got errors that I could ignore, but never the second error or crash. Now, the OGL canvas gives me an error that I can ignore, and no longer crashes.
Sooooo, I get that it may seem unrelated, but I can not confirm that on my machine at this point in time. I'm certainly not going to withhold any issues I find. But, I do get it, sending you down the wrong rabbit hole could be a colossal waste of your time.
Hope you can nail this one down quickly.