The device turns on but does not turn off using the switch

Have just got a second hand Veho Muvi K2 NPNG action cam, it is in pristine condition and functions mostly as it should. However, one annoying niggle I have with it is that the on off switch at the front of the cam does not turn off the camera. It functions well enough to turn it on but not to turn it off. I have used these cameras in the past and it was possible to turn it off using this switch. I have done a factory reset and am thinking about a firmware patch to see if that helps but I was wondering if the hive mind had any other ideas? Am thinking about taking it apart and seeing if there is anything loose. Don't really want to return it as it works well enough and I got it for a very good price, just a bit annoyed with this niggle.