The twitter picture (arguably) suggests that there were two impacts: the first in a conventional impact with the girder of the airbridge which damaged the inlet cowl, and the second from above which damaged the top of the fan cowl. The pattern of cracking of the fan cowl does not suggest a lateral impact.
So the mechanism would be that the aircraft was moving, hit the airbridge, braking was applied, the nose dipped as PFP suggests, then rose back up for a second impact.
"The aircraft moved slightly after parking". Nice try. The pictures suggest otherwise: that it hit the airbridge before it stopped.