These are images from my test bed, white mark on the disc is the magnet.

Only get one pulse per pass from my unit, no problem here.

Maybe those that are having multiple switching should do some iron filing tests.
See where the stray magnetism is coming from.

My bet is too large or too strong a magnet.
Also remember the steel shaft under the aluminium collar will re-direct magnetic lines of force if you have the magnet installed in the outer circumference as Rob's videos show.

I always run my systems with the magnet installed on the side face of the aluminium dics. This does 2 things.
1...stops the magnet flying out under centrifugal forces and
2... stops any re-direction of the magnetic flux.