An issue with the MAC QT Wallet has been found and fixed. Please visit the BitBay Market Download page for the latest version. This was related to a security patch in the Wine Bottle build. It is recommended not to transfer BAY into or out of your QT Wallet until after you have updated.
This issue did not affect the BitBay Marketplace Client. You will only need to update if you are still using the MAC QT Wallet.
The QT Wallet is essentially obsolete now that the Marketplace Client allows staking. The core team recommends moving your BAY to the Marketplace Client after running the update.
Please contact a member of the BitBay core team on BitBay Slack or Bitcointalk if you have any questions.