Predator x27 bmiiphzx and HDR (destiny 2 and ALT-TAB)

Sumguy31

Acer Predator X27 bmiiphzx 27" LED Monitor 

I've been enjoying my X27 running Destiny 2 in 4K + HDR and it looks fantastic.  

The issue i'm having though is when I "ALT-TAB" from Destiny 2 back to windows 10, the screen will blink for 5-10 seconds so almost like its resetting its own resolution and settings.  Same happens when I go from Windows 10 back to Destiny 2 pressing "ALT-TAB'.
Its very annoying especially when you in are in battle and need to switch out or switching to Discord, etc...

Is anyone else having this issue?  And is there something I can do to address this?  This doesn't happen when I have HDR disabled with 4K.  Seems HDR is the issue.
Its been doing this since my purchase.