Neu 1512, 1.5d magnet force

I just recienve my Neu 1509, 2.5d t my 1512, 1.5d.
Like all my other Neu that i had, the 1509 rotor is very hard to turn by hand, but on the 1512, the rotor is very easy to turn by hand, like if the magnetic force was not as strong as the 1509 or my previous 1515, 1y, and 1515, 2.5d.

Is somebody here have a 1512 and have experiment this??

Thank you