Hi, you don’t mention the system details or OS. Is the project and clips fine if you open the project again?
There is a known GPU/OS issue in the sleep process that is out of the Resolve app control and it might be this you are seeing. We recommend you turn off the energy saver settings and before you complete your session, save the project and exit. Then open the project cleanly when you next come back to the machine.
If this is not the issue you will need to offer some more detail.
Peter