This problem sounds impossible actually, I can't think of any way a bug in Factorio, Factorissimo2 or Bob's Logistics could cause this behavior. I have some ideas though: Is there enough free space in your roboports for the robots to stay? Are you sure your factory buildings are set to receive enough power for the robots to charge?
If this didn't help, maybe you could help me by providing instructions on how to reproduce this bug in a fresh world, using sandbox mode or the editor.