This add-on has the same problem as Temporary containers. If you want to isolate Facebook and click a link to Spotify it will open Spotify in the Facebook container :(
So far only the Google/FB container add-ons do this right.
So far only the Google/FB container add-ons do this right.
https://github.com/stoically/temporary-containers/wiki/Globa...
If you are talking about the Temporary containers extension, that's not the case. The extension is not the most easy to use, but it certainly supports opening Spotify in a different container when clicking a link in FB. You either don't have the Navigation→Target Domain set to Different from Tab Domain & Subdomains or you have Exclusion Patterns set which exempt Spotify.