2725qc and mac - insane colors

Every time I update the MacOS the screen colors go insane.  The monitor becomes almost useless.

The first time it happened I was able to return to normal using Self Diagnostic.  The second time that didn't help.

MacOS 26.0.1.    M4 Mac Mini.

I've done a Factory Reset of the monitor.

I've done a Hard Reboot of the monitor.

I've done the Self Diagnostic.

I've switched from USB-C to HDMI.

I've switched USB-C cables.

I installed DDPM for MacOS and I can access it.  Everything appears normal.  It does say 2.1.1.0007 is available as an update.  I can download that but when it asks if I want to Update Now nothing happens when I click the YesÎ button.

An oddity.  After restarting the Mac Mini, the screen colors are completely normal.  However, after I enter my password and the screen goes to the regular layout then the colors go insane.

I've used this Mac Mini with a prior Dell monitor 2719DM and had no issues.

If I plug my M1 MacBook Air into the monitor then the colors are normal.  Updated to MacOS 26.0.1 and colors are still normal when I plug it into the monitor.

To summarize:

The 2725QC worked fine with the M4 MacMini and MacOS 18.  

Colors went insane after updating to MacOS 26.

Using Self Diagnostic, was able to get colors back to normal.

Updated to MacOS 26.0.1 and colors went insane.

No problems with using the monitor as an external screen with an M1 MacBook Air, even after OS updates.