What does this behavior indicate?

Hi, just picked up this 1926 Sol from Peru, 24.8g, .500 fine.  I did the magnet test as I do with all my silver coins, and I saw this strange behavior.  Normally it slides down smoothly, but it seems to be catching at one point.  Is this an indication of a counterfeit, or is it maybe just an anomaly in the composition?

https://youtube.com/shorts/NtI-LtBTzM4?feature=shared

There is 10% Nickel in the composition unusual for silver coins.  Not knowing how the three elements behave together (crystal structure, single phase or multi-phase structure, etc.) I cannot say if this behavior is normal. However, I wouldn't different properties at different locations in a 20th century milled coin.

N#4639

Data point for you:

I have 3 of this type, and none exhibit any magnetic behavior with a very strong 20mm neodymium magnet.

I found this discussion on another forum.  Turns out it's not unheard of.