This occurs when the Logitech BRIO 4K Ultra HD webcam is plugged into the external monitor USB-A port and the monitor is connected to USB-C with display port using the monitor USB-C cable. The Dell monitor's USB-C prioritization default is High Resolution . With this configuration, the Logitech BRIO 4K Ultra HD webcam cannot be set to 4K for photo or 2K for video with the Windows Camera application.
This does not happen when connecting with the Thunderbolt port.
The Dell monitor USB-C prioritization default is High Resolution . The High Resolution prioritization downgrades the USB hub speed to USB 2.0 from USB 3.0 speed. The USB 2.0 speed cannot meet the 4K bandwidth requirement.
Connect the camera directly to the computer.
Alternatively, change the
USB-C Prioritization
to
High Data Speed
from
High Resolution
in the monitor's on-screen display (OSD) menu.