Photoshop 22.1.1. - screen flickers while working on apps outside Photoshop on macOS

I have Photoshop 22.1.1 running on a late 2015 iMac 27" (3.3GHz, 32GB RAM, AMD Radeon M395 2GB graphics) with an external Asus 1440p monitor connected via Displayport. I'm having an issue with Photoshop periodically flashing constantly between the image I'm working on and black every half second or so. From my experience so far, this happens when I am working outside of Photoshop (as I type this it's happenning sporadically). The moment I click into Photoshop, it stops. I initially thought that it was because I've only just recently acquired the 2nd screen, and that because the graphics card only has 2MB RAM, it might be struggling. However, this is only happening with Photoshop. Is this a known glitch? If it is, I'll downgrade as this has only started happening within the last couple of days, even though I've been using this version of Photoshop for a little while. Thanks in advance.

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