FIbaro Shutter 2 calibration: upper/lower limits drifting

I’ve got 4x “Fibaro shutter 2” and 2 of them seem to have a calibration issue. I’ve re-calibrated within HA but no luck. One of the blinds seems to be “drifting” from its original references (i.e. lowering too much and rolling up too much).

I’ve also tried to limit this via the parameters 156 ( Time of up movement ) and 157 (Time of down movement). But I don’t think this is where I need to fix it… it doesn’t really fix the problem.

I’ve also heard that the upper and lower limits are calibrated on the (Somfy) motor itself…so nothing to do with HA nor Fibaro Shutter. But I don’t know how this is done.

Has anyone had a similar issue? can shed some light?