swoosh sound on outgoing emails

Any Third Party Applications that will interfere with the normal operation of the OS, alter, modify, remove or delete or attempt to do so is an invitation for disaster and may require a Reinstallation of the OS.

This includes AntiVirus, Disk Cleaners, Disk Optimizes, UnInstaller etc.

This will include CMM

The The Built in Security  is all that is required.

Has one tried booting into Safe Mode and testing if the issue is presented ?

Restarts are quick and painless. In the time it takes you to post and get an answer, you could have already done it and found out that way.