Namespace "Email All" misformats emails on Outlook

This is on the Outlook desktop client (v16.75.2) for Mac 13.4.1. When I click mail all, I see this:

When I double click it, it seems to fix it by changing it to: ; Jialong Li jil316@ucsd.edu; Which is tedious for large email groups.

Maybe outlook prefers ; over , ?