I'm not into this but once discovered a kind of security related bug (could reveal details about the composition of a password typed into a new Windows 8 password field, admittedly low value as you had to have the user type in the password and leave) and later found a more interesting issue in the way an official powershell module works with Azure Information Security that makes it possible to sneak a file through unencrypted.

On the first I got a nice thank you mail and on the last I struggled so hard to report it that I gave up.