The Protonmail Bridge with Thunderbird (the only somewhat supported desktop mail client on Linux) has always been buggy at times, such as archiving not working as expected, or creating a new mail subfolder in Thunderbird creates a parent folder with a "/" in front of it in web mail.
I understand there's probably some difficulty keeping everything E2E encrypted on the desktop side of things, but Thunderbird feels crippled if you want to use it with Protonmail/Bridge. For example, calendar doesn't work at all.
I love what Protonmail has been trying to do and have done, but all I really want is to be able to use a desktop mail client with calendar, and the Protonmail Bridge is not there yet. My subscription is up in January, so I may switch to something like Fastmail for the time being.