Precision 7510 External Monitor not holding resolution
I have a Dell Precision 7510 laptop with the TB16 dock.
I have the computer connected to two external display out of the dock. 1 - is a 4k Dell display connected to the dock with a mini display port to display port cable at the monitor. 2 is a dell FHD monitor connected via HDMI
When I first turn on the computer or restart the computer the display appear correctly. The 4k in 4k the FHD in FHD. I leave my computer on while I am in the office and if I run out to a meeting or something I have it go to sleep after 10-15 minutes. When I move the mouse it wakes. What is not right is when it wakes the 4k display goes to 1920x1080. I open the NVIDIA control panel and it sees the display, but it does not give me the 4k resolution as a usable resolution. The highest it goes is to 1920x1080. I then have to restart to get everything back to how it was. This is very annoying as the main reason I have the 4k display is the high resolution I need for graphic design and it really causes issues.
Anyone have any idea why this is happening or what to do to stop it?