There was flakiness in tests which appears to be caused by the actual slowness of the app:

The reason is that the https://www.googleapis.com/gmail/v1/users/me/settings/sendAs request sometimes takes quite a white, I personally experienced 12 seconds locally, but in CI it sometimes takes more than 20 seconds, example: https://flowcrypt.semaphoreci.com/jobs/9f63948c-b6c9-4123-8d67-236e1985c5b1
Not sure if this is something that could/should be fixed, reporting for the reference mostly.