I can confirm this behavior in Ubuntu 14.04 and thunderbird 45.8.0 In Windows 10 with thunderbird 52.0.1 this doesn't happen. I don't use 2 factor authentication.
I can confirm this behavior in Ubuntu 14.04 and thunderbird 45.8.0
In Windows 10 with thunderbird 52.0.1 this doesn't happen. I don't use 2 factor authentication.