Mozilla released an update to Thunderbird 11.0 on March 28th to address a couple pesky bugs:

• bug 733731 – Fixes an issue that may cause hangs when handling IMAP mail
• bug 735940 – Fixes an issue that may cause filters that move mail to specific folders to be erronously (sic) changed

I had not run into issues with the first bug, but had heard from users who were affected. The second bug, I had run into on the laptop, especially when Thunderbird was trying to re-sync my IMAP accounts upon resuming Windows from hibernate mode. There were a couple times I had to force Thunderbird to close and then restart.

Existing Thunderbird 11.0.x users can update by going to Help > About Thunderbird. The next schedule update is Thunderbird 12.0 on April 24th.