I think it's probably going to be several different issues with other products and Malwarebytes 3.
Just a feeling that the "hooks" or apps that the new features present are conflicting with other software that references similar or same.
I've seen some people say it's a certain software that triggers it when I don't use that software.
As previously noted, Malwarebytes Pro has never had any issues for me in playing well with my environment.
I see a few choices left for me:
1. Run Malwarebytes Pro
2. Turn off Malwarebytes 3 Exploit Protection until future release fixes Task Manager hanging Firefox processes.
3. Kill processes manually when they stay in Task Manager after closing in order to restart browser when needed, so I can periodically run CCcleaner after say, doing banking or paying bills to clean up trails.
For right now I have chosen option two, because it seems less onerous to me.
I do two full disk to disk (offline) backups a month and prior to MS patches and any software changes along with periodic system restore points.
I have never had a virus or any other problem since computers first required math co-processors be inserted separately and have built my computers from scratch.
In my life as a Vax Digital Mainframe manager and Systems manager, V.P. in banking for over 30 years for Mercantile/Mbank/Chase I've always incorporated good backup procedures and rotations.
Malewarebytes is a good product and I look forward to seeing the "Exploit Protection" issue addressed or defined. Perhaps a feature that will output software names and app conflicts that it encounters since I've seen a few responses of "other software is not properly accessing apps and leaves hooks that don't consider that Malwarebytes 3 might utilize them".