Co-Axial 2500 magnetism question

I’m sure this a somewhat tired subject but I haven’t been able to find as much info as I like.

I recently had two mid size aqua terras (2504.50/80) with the first gen co-axial 2500 movements (C & D variants) serviced by omega. One watch was running fast and apparently was magnetized and the other is also running fast and I suspect that it too is magnetized. I’m a little baffled that this could have happened, twice. I know we live in a modern world with everyday items that contain magnets. However, I haven’t had magnetism issues with any of my other automatic watches until now.

Does anybody know if and what anti-magnetic properties the co-axial 2500 movement contains? As in what guass am I protected up to in these movements.

Also, what is the best affordable anti-magnetism device that I can purchase for leas than $25-$30. There’s a bunch that all look the same but with varying reviews.

I like this one:

https://smile.amazon.com/Demagnetiz...hanical-Watchmakers/dp/B08ZJ6GYS8/ref=sr_1_17

You'll find the exact same thing at wildly differing prices. I'm semi-convinced they're all made at the same factory.