I still use my strong bar magnets all the time, but I limit them to the side and bottom. Anywhere the fan may pass over I avoid, using non-magnetic solutions if necessary.
I stopped selling them after Glowforge made changes that caused an error sometime with the air assist fan. Now, I use these magnets all the time, but only on the front half of the machine. I didn’t want anyone to waste material getting this error, and then blame it on the magnets. Sorry!
Wouldn’t a little piece of thin steel or aluminum in the place of the insert on top of the magnet prevent the magnetic field issue from impacting the fan?