I'v bought it directly from Axi Model Motors, at their web shop
www.modelmotors.czRecently got their response about the issue, saying "there are some signs of surface damage caused by poor handling of this motor. It is obvious, that the plastic fan is damaged mechanically".
But those signs was just a result of me trying to take out that loose part of the fan with tweezers, because I did not want to disassemble the motor.
And now comes the funniest part of the story. This is what they have written to me regarding those burrs:
"We produce quality motors. Your the trouser also have signs of production inside."
Cheers,
Vitalis