o365 programs not recognizing Jabber for tel: links

I'm trying to set Cisco Jabber to be the default application in Win11 for the tel: protocol, specifically for Excel. The first time I tested this, clicking the link opened correctly in Jabber, but every time afterwards pops open a blank Edge browser. Swapping the default program to Teams or Skype for Business works fine, but breaks again as soon as I swap back to Jabber. The default is correctly listed as Jabber in the registry under HKEY_CLASSES_ROOT\callto\shell\open\command.

The issue seems to be limited to Office, I've tried tel: links in PowerPoint and Word with the same results but trying a link from a web browser correctly opens Jabber. Anyone have any ideas as to what might be going on here?