I have multiple robots that are running very similar programs. They all seem to be stopping randomly throughout the process. The program could run multiple  times and will not stop in the same place. It seems to happen at planned stop locations and between two waypoints.

Any ideas to what this is?

I found my suspect it seems that the safety mode is being quickly changed .02 microsec from safeguard stop to normal mode

Are you using a safety controller with the robots?

I'm using a safety relay which the one being used is allen bradley MSR127TP 

We’ve seen that issue when we use solid state safety relays, it’s due to checks they run on the circuit. We use the Banner XS26 safety control system and have to use the actual contact type safety relays with it, we can’t use the OSSD type outputs for any of the safety on the robot.  We have used Banner safety relays successfully, the contact type without edm.  

Interesting I'll look into it.