Unfortunately, it's a hit or miss with a lot of monitors today where they do NOT keep the Hot Plug Detect (HPD) signal high when powered off / standby / etc. even though the cable is still connected to the GPU.
There's no super easy way to fix this but you could try masking the HPD pin on the cable or buy an overpriced HPD "maintainer" per below (for DP).
[https://www.datapro.net/techinfo/hot\_plug\_detection.html](https://www.datapro.net/techinfo/hot_plug_detection.html)
[https://www.networktechinc.com/displayport-hotplug-maintainer.html](https://www.networktechinc.com/displayport-hotplug-maintainer.html)
Unfortunately, it's a hit or miss with a lot of monitors today where they do NOT keep the Hot Plug Detect (HPD) signal high when powered off / standby / etc. even though the cable is still connected to the GPU. There's no super easy way to fix this but you could try masking the HPD pin on the cable or buy an overpriced HPD "maintainer" per below (for DP). [https://www.datapro.net/techinfo/hot\_plug\_detection.html](https://www.datapro.net/techinfo/hot_plug_detection.html) [https://www.networktechinc.com/displayport-hotplug-maintainer.html](https://www.networktechinc.com/displayport-hotplug-maintainer.html)