For a team's Sharepoint site, I created an issues log (create -> app -> issues log) and customized it a bit, including adding a managed metadata field). Back in Teams - if I try to add the sharepoint list as a tab - it does not show up in the interface as an available list:
However, if I go to Site Contents for this team:
and there is that list (Issue Log).
I am able to add the list using either the "Add page or list from any SharePoint site" button, or as a web page tab. However that creates a different problem:
When adding it this way - if I edit a record and click on the button to open the term store for that field - it flashes for a second the loading of the term store, and quickly switches to a request/reproting dialog for the term owner (me) and the buttons/fields in that form are disabled. Clearly some kind of embedded access issue.
If I open the same form directly in a browser tab - it works perfectly so this is not about the site's access to the term store
Here's what it looks like - a recording of the tab with the embedded sharepoint list page:
Here's the same list - open directly in a browser window: