I contacted Sharp/NEC support. Even though these projectors were discontinued they did help me upgrade the firmware on them to the latest version. This has appeared to fix all of the issues in testing. I am waiting for the other staff to connect their computers to verify but this appears to be a problem with old firmware on the projectors.
Have the Dell Latitude 7320 Detachable and trying to get it to display to an NEC M322W projector. Have tried a straight USB-C to HDMI cable, a Dell puck style adapter that came with the laptop, and also a TWOPAN USB C Hub HDMI 4K, 5-in-1 USB C to USB Hub 4 Ports adapter. All with the same result. The screen is mirrored to the projector for a second or two then flickers then the video shuts off. I cannot tell whether or not the laptop is shutting off the video or the projector is doing it. If I leave it alone the video flickers, shuts off, and then comes back on and repeats. I have already updated the video drivers on the laptop and also the BIOS and chipset to the latest versions (as of this posting). I have checked the NEC M322W documentation and even though it's an older projector it is compatible with the output of the laptop at least according to the manual. This is in a municipal environment and we have two of these projectors that are used for classrooms. So far we haven't found a solution and will have to replace them if we can't get it to work. The kicker is we have two NEC ME401W and two Panasonic EW640 WXGA projectors that all work fine no issues. I am thinking the problem is somewhere with the NEC M322W. Of course Sharp/NEC has discontinued the M322W so no help there. Just looking for any information that might help. Thank you
Latitude 7320 Detachable - USB C to HDMI - NEC M322W Projector