fractal only receives new messages when syncing after startup
Since March 19, 2019, my fractal 4.0.0 (installed from flathub) no longer receives messages except when syncing during startup. After "Syncing, this may take a while" completes, fractal receives all new messages properly, but it will never receive any further messages from the server until it's closed and restarted.
fractal is still able to send messages perfectly fine.
fractal version is 4.0.0. Build date is 2019-01-02 and org.gnome.Platform//3.30 build date is 2019-03-09. So there's no recent software update to blame. It seems fractal just picked March 19 to stop working for some unknown reason. :S