Hello, I switched to Thunderbird a few months ago. Since the beginning I am having a weird issue. When I perform an action on an email, like marking it as read, or sending it to spam, there is a chance that this action just reverts after a few seconds. '''Example:''' I click on "mark read" for an email. The email shows as read. A few seconds / minutes later, the unread icon pops back up and shows me the email again as unread. I then have to click "mark read" again. This process (sometimes) repeats itself, meaning I have to click like 3-5 times on "mark read" until it actually stays this way. I don't understand why this happens after some seconds / minutes (every time this happens the time also varies). I'm guessing maybe this has something to do with Thunderbird being incompatible to my mail provider (Yahoo)? Maybe something like this is happening? I click "mark read" -> Thunderbird syncs this change to my Yahoo IMAP server, but this fails for some reason -> Thunderbird checks periodically for new messages -> overwrites the local state of the email with the IMAP server state -> email is now unread again Some more information: - I tested both Thunderbird 78 and 91 - I also tried completely setting up a new profile - I tried restricting the number of mails synced offline to the last year, in case Thunderbird has problems handling large inboxes - I enabled and checked Thunderbird logs via ''export MOZ_LOG_FILE'' and ''export MOZ_LOG=IMAP:4'' but didn't find anything helpful (please advise what to look for) - I am using my Yahoo mail account since over 15 years and never had this issue with other mail clients like Mailbird, Opera Mail, AquaMail (Android) or FairEmail (Android), so I doubt its a Yahoo issue All this did not help. How can I fix this? Are there any settings I could try? It is really driving me crazy having to redo the same actions over and over again. Thank you :)