Three Jaw Chuck (4th axle) mech playning

Hi everybody. I have installed the 4th axle unit (three jaw chuck), but after about 20-30 minutes of working time a little mechanical play as appeared. At the beginning, no mechanical playing was present. Please see the video here attached.
Do anyone of you have the stepcraft 4th axle ? Do you have the same mechanical playing ?
Thanks
Nicola
Video here:

https://www.dropbox.com/sh/3xy6qc50ylig2wr/AACNQBKaff1pfd_2crdmKlJ5a?dl=0