Hedi driver errors in Civil 3D 2014 on K100 profile

XenDesktop 7.5 – HF 04 and 11
XenServer 6.2 – HF1009
K1 Card using K100 profile and vGPU driver 332.83 and 6.2-331.59.01

VM’s have 10gb and 4 cores dedicated to them and we are running Civil 3D 2014 SP2. We have one user that every once and a while gets the following error:
“The configured Heidi driver cannot be loaded. Switching to default software driver.”
Hardware acceleration then becomes disabled and the user has to re enable it. Civil 3D never crashes and they can get back to work. The problem can occur at any time even when they are actively working on another program on the 2nd screen or not even using the computer.
In the past, we would look into upgrading the video driver but it seems that I am running the latest. Does anyone have method to trouble shooting this?