What extraction rule are you using? I successfully extracted a user with the user tag extraction #O365_MeFlexPane_ButtonID@title in outlook. The session shows up displaying the proper name ("Scheurer, Simon") - I was recording my own outlook using the extension
I will check with this setting as well. Please note that you can set several rules. The first matching rule will be used. Ie. you do not necessarily need one single rule that matches all tools. For example you can add my suggested rule as well which will work in several of the products and then starting to add more specific rules for the ones that do not match.
This works well also on the planner. Extraction works without problems in my extension.
Some additional questions:
Do you have "Do not track" settings enabled in your browser?
If in the application settings --> Data Privacy --> "Comply with 'Do Not Track' browser settings" is enabled for your application, then the user tag will only be extracted for browsers that do not have the setting activated.
Thus please check that you either have the "Comply with 'Do Not Track' browser settings" disabled or check in your browser whether do not track is set to on (in Chrome: Advanced Settings --> Send a "Do Not Track" request with your browsing traffic)
Thus in summary: The extraction rule needs to be on, but also the do not track settings matter to decide whether we extract the user tag at all.