Ah, that's an interesting data point, I had incorrectly assumed that the problem was triggered only when upgrading to Ubuntu 20.10.
@Joep, can you share the output of the following command?
apt policy thunderbird
Ah, that's an interesting data point, I had incorrectly assumed that the problem was triggered only when upgrading to Ubuntu 20.10.
@Joep, can you share the output of the following command?
apt policy thunderbird