New 3.7 bug: If Mu3.7 is running, clicking on MSCZ file fails to open

I click on an MSCZ file, and it launches Musescore and opens the file. I click on another, and it doesn't.
Or:
I launch Musescore (empty). I click on an MSCZ file, and it does not open.
This happens using File Explorer (and Z-Tree) in Windows 10 & 11
Observed in v3.7.0.11299493561 - ba6d337 and later (64-bit).

3.7.0.11258847346, 009a9bd and earlier work OK.

LMK if I should enter this in GitHub.