After upgrading to endless-os 3.2 there is an update reminder for “Gnome Application Platform version 3.22” stuck in the appcenter/gnome-software. I tried several times to klick the update button, as well as all updates, restarted the program and the machine but to no avail.
Can you run flatpak update in the Terminal and paste it’s output?
I have also noticed that flatpak updates are painfully slow and unstable. It took me about three weeks of almost daily attempts to get the org.freedesktop.* flatpaks to finally succeed. I have better luck overnight for some reason which leads me to believe it is related to bandwidth. It seems that the timeouts are too short somewhere in the process and retries start to pile up until the procedure fails.
Basically, I think the whole software update process and package management in Endless OS needs some attention. And although I understand they are not the target audience for Endless, the OS is not particularly friendly for developers.