New Gold Plus - one device attempting to connect to others

Hello to all,

New user here, love my new gold plus so far. Also pretty green when it comes to networking, please go easy on me!

Had some security concerns that prompted the firewalla purchase, all of those are ironed out now. Was just about to put this thing on cruise control, when I found one of my PC's to constantly be scanning/attempting to connect to any and all devices within an IP range of about 20 numbers.

Found this just after I happened to isolate 3 of the my wired/ethernet pc's onto their on firewalla port, at which time I had setup a rule for no communications to or from any network. I instantly started getting blocks on that rule. Over 50,000 hits in the last 12 hours on the one pc, nothing at all on the other 2 pc's, which are setup nearly identically, and see very similar use. All 3 are windows 10 and 11 pc's. I ran malwarebytes and Norton scans, both were clean. Updated all drivers. No change, still getting blocks/hits.

The more concerning part about this, and this is where I get in over my head - when I open up the details on any of the blocked attempts, the destination for every single one lists my canon printer's mfnp port. I know/understand nothing about this, but have read that this can be a security weakness?

Can anyone offer any tips on what to look at next? I very much appreciate any help.

Thank you!!!