Command block set to repeat will randomly stop working. 

I have been making a map for 5 months now with many repeating command blocks. I updated to 1.14.1 and whilst working on my map suddenly most if not all repeating command blocks stopped working. They would update if I turned them off and on again, or simply powered them with a redstone block. BUT again they stopped working. Luckily I made a back up, and I only wasted 7 HOURS of my life trying to work around it.

I am forced to stay in 1,14 until that issue is fixed.