User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.71 Safari/537.36

Steps to reproduce:

having a label that includes "/" (slash) in the name in gmail for eg. x/y

I am on thunderbird daily version 95.0a1 (7 Oct 2021). This bug might be in the previous versions as well.

Actual results:

thunderbird marks the folder as phantom folder (grayed out italic) and the emails are not downloaded

Expected results:

folder should appears and would sync as it would normally

My fix was to rename the label in gmail without having the "/"

My guess is that the slash is causing thunderbird to interpret it as the server path containing a different folder (in my case x would be the parrent folder and y the child) and both labels would not resolve to contain any email.

Normally this could be fixed in the thunderbird code by escaping the slash somehow.

Indeed, this is bug 1512053