mam.py has a filter to check if two SOPInstanceUIDs with the same StudyInstanceUID have the same event time. If so, they are assumed to be the For Processing and the For Presentation versions of the same exposure.
With Hologic ComboHD mode, one exposure button press launches a tomo series of exposures followed by a conventional 2D image. The 2D image and the SC proprietary projection image object are sent separately to the dose server, with different SOPInstanceUIDs, but with the same event time. Therefore the are caught in the For Processing/For Presentation trap.