Strange purple glitching when in remote sessions

I have one user out of 12 that I have this problem with. All of the users are using Dell Laptops. All are using an additional monitor. This user is using an LG monitor that has a 75 Hz refresh rate. All the rest of the users have a 60 Hz refresh rate monitors. The laptop's built in screen is a 60 Hz. refresh rate. I assumed it was a driver issue so we attempted to make it go away. It did not. We had her shut down the external monitor but the problem persisted. The final resolution came when we had her shut the clam shell on the laptop forcing everything over to the 75 Hz refresh rate. The problem disappeared. This may or may not help anyone else but we have been able to duplicate the issue with this high refresh rate monitor and work around the issue by simply forcing the client to use the higher refresh rate monitor. I believe this problem (for us) was the fact that we had two different refresh rates and the remote software didn't know how to handle that. Once it was a fed the higher of the two rates it had no issues.