@joepie91 I have seen different variations of this.
The one I experience the most often is that favs are present, but not displayed correctly, so faving again actually unfavs a toot.
A related issue is faving a toot and it not being properly inserted to the redux state, so it immediately vanishes.
Then there seems to be an issue where you fav something, but it actually never gets send/processed by the server, so it's just present in the state and therefore vanishes after reloading.