Same problem here. 

I use Gmail on my BlackBerry, along with a device level peer-to-peer encryption software.  IMAP is creating a problem though because it is stealing the decrypted data from my device and updating the server with it.  Not good - that's compromising my privacy and the confidentiality of my emails.

None of the fixes are working.  Disabling the setting IS pointless because it just resets itself randomly.

This is an issue Gmail needs to address and quickly.  Obviously it has more serious ramifications than just inconvenience.  It's crossing over to the domain of consumer privacy rights.