If magnet come loose from motor can it meaning two problem. the first problem is about epoxy use. if not for high temp and curing proper it can fail. for second is about motor can thick. if material is too thin can cause indent to can which can loosen magnet. most motor make with bar magnet so it need many epoxy to fill in space. if motor make with radial magnet liking ours it fit with smaller gap having. and you not having this problem.
for this hub motor we make main can from thick steel. for end is made from 6061-T6 alu. we very confident for this motor. we provide epoxy to motor factory that we using already and teach them how to using. for sensor we also cover for epoxy to keep protect from moisture and dirty. my engineer is work with the factory to make this motor to our standard.