Thanks for posting! I’ll be glad to assist.
We’ve seen several other reports lately of Surface systems not outputting video through the dock (all seemed to be related to Windows Update sometime in the last couple weeks). The reported symptoms match what you’re describing - Windows “thinks” the monitors are present and functioning, but there’s no output to the displays. In the other cases installing newer Intel video drivers has helped to resolve the issue, so that will be our next step.
We have a blog post including a video that describes and demonstrates the driver update process step-by-step:
After updating the Intel drivers, please let us know if the monitors return to working as expected.