I've chatted with Samsung support and confirmed that the following issue is isolated to this monitor. We've reset the monitor and verified that the firmware is current. Also updated AMD display driver on laptop and ran Windows Update and Lenovo Vantage updates.
I've attempted to connect via HDMI directly and DisplayPort via Lenovo universal dock. The following issue persists...
The Samsung monitor works fine in "Extend" mode (laptop open) at full 5120x1440 resolution.
I have the "closed lid" options all set to "do nothing". If I set the display to "2nd screen only" or close the laptop lid, the ultrawide goes black. It will only work in extend mode. As noted above, "2nd screen only" (closed lid) works fine with other external monitors.
