Rated 1 out of 5 stars

Unfortunately for me, I found the same issue as the other persons reported above. First time for me to switch from Evolution to Thunderbird in Ubuntu 20.04 in order to manage my contacts, and one page on the web points to Cardbook to improve contacts management, then it doesn't work, then I find the messages here.
As for your gitlab page I can read the bug was closed yesterday.
I'll continue using Evoution then.

This review is for a previous version of the add-on (92.1). 

Hi
may you contact me by email, as I can't reproduce your issue...