Version 14 is a piece of JUNK.
It crashes all the time. Especially if you do any rendering which is, kind of, necessary!
This crash followed two renders of the same loop region, one at 30fps and one at 60fps, 1080P, XAVCS template. 4K source material.
It looks like the only way to run v14 is to render and then exit and restart the program.
But there are many other things which cause it to crash.
I will have to go back to v13, but that didn't seem to do 4K rendering (which I don't need much however).