New 1717 with loose rotor balancing putty - please advise

[Dr_T]

Hi,

I received a new Castle 1717-1650 motor today, bought at a US "chop-shop". It made a bit of a rattle, so I opened it up and found the rotor balancing putty had come loose. The motor should be new/unused and it doesn't look like it was handled roughly or dropped.

Is this a typical thing or just bad luck? Last pic shows comparison of the front putty and the rear putty that came off; front looks to be applied smoother, not sure that indicates anything particular, but it was just something I noticed.

Main question: is this something I should be able to easily fix myself (marks on the rotor do show where the putty was, see second pic) or better send it back for a replacement?

Appreciate your help.