On my setup with HifiBerry OS 20210408 the now-playing screen on the we server and and the connected display stops updating after some time. After some time means something between 2 and 10 songs.
This means, after playing some songs, the now-playing screen displays constantly older song title and cover art.
This occurs for Airplay streaming and DLNA steaming. Other sources are not used. Only a restart of RPi solves the issues for some time.