Mac Desktop - Screen flickers when Signal app is in focus

[plmcgrn]

Using a supported version?

• I have searched searched open and closed issues for duplicates.
• I am using Signal-Desktop as provided by the Signal team, not a 3rd-party package.

Overall summary

Same behavior as #7001 , but not related to HDR image viewing.

I'm having this issue as well, on MacOS 26.0.1 and Signal 7.74.0 on a 2024 Mac Mini M4 Pro connected to a 1080p monitor.

Signal is my only app causing this full screen flicker, and far from the only Electron container-based app I use. Other Electron apps like Visual Studio Code, Proton Mail, Bitwarden, and others do not have this flicker.

Steps to reproduce

I've noticed a few patterns here, so I'll just note them and hope one of the devs can see a broader picture of the issue.

1. Setting Signal's app zoom to default using Command + 0 makes the flicker go away. If I use Command + + to zoom in two times, flicker comes back. I'm not sure what zoom level that is, assuming 150% if it goes in increments of 25%. I cannot repro at any other app zoom level, including bigger ones.
2. If I disable Night Shift, it goes away, even if Signal's app zoom is at the level that'd cause flicker in item 1. I believe the flicker is actually the display flickering between Night Shift color hues and default color hues.
3. If I use full screen zoom Control + Scroll (accessibility feature) to zoom in about 10%, the flicker goes away.
4. Sometimes the flicker goes away on its own, but I've yet to find a reliable trigger to force that, short of items 1 - 3 above. By the time I finished writing this up, the flicker had gone away on its own, I could only triggering it by powering my monitor off and back on again.
5. Taking Signal out of focus by switching to another app immediately stops the flicker, and switching back will resume the flicker.

Expected result

No flickering

Actual result

Screen flickers

Screenshots

No response

Signal version

7.74.0

Operating system

macOS 26.0.1

Version of Signal on your phone

7.80 (1077) iOS

Link to debug log

https://debuglogs.org/desktop/7.74.0/7cd82a11bf8029e4a37e99da6c476b73a992a0f33701d298683e7d3d8d2fe608.gz

This was generated after power cycling my monitor and observing the flicker.