Chiming in with the same issue. Meticulously and correctly installed, checked everything. Got some great video over the course of last weekend, about 40 minutes worth.
Yesterday, went to power it up and it made the loud squealing noise. Mine is still responsive, still tilts and rolls, but makes that high pitched squealing sound when the quad sits level. While it's level and making the noise, the roll motor seems to get very hot very quickly. The tilt motor stays quiet and runs cool.
Called up the dealer. They tell me it's a somewhat "common" problem and that DJI is working on a firmware fix which should be released in the coming weeks. Latest should be within the month. They also tell me this is the reason for the delay in the next batches of gimbals.
Not sure what to believe at this point but that raises a flag to me. Whether DJI really is working on a new firmware, or whether the new firmware will fix my gimbal which is already making the squealing noise.... I don't know.
Dealer says I'd have 6 months to return the gimbal if it really is defective. I can play the waiting game for the new firmware, or de-solder the whole **** thing and ship it back. That's a lot of work, but I'm tempted to do the latter right about now.