Thanks for all the details. After seeing your post on Plex forum I did some tests and effectively found that only song play status are working Plex is not properly updating album / artists from those played songs despite calling the proper known end points.
But song playing status is correctly updated on Plex and Yatse side for sure.
For consistency in AA the recently played will switch to displaying songs, as it better works with playlist anyway now that I’ve added them to AA too.
It’s nice to see that Plex works correctly from the web interface I’ll be able to look into what they do differently and hopefully fix the other part of Yatse that display recently played albums.