This PmProfileFieldMapBasicPtp field is a bitmap indicating which specific fields within this Basic PTP history profile were marked invalid (untrustworthy) for this particular bin. Because this row is a closed, completed interval from the PTP performance-monitoring history table for this timing session, a bit set here flags that whatever value appears in the corresponding field for this same row — even if it looks like a normal number — was affected by a data-collection problem and should not be trusted for trend analysis or alarming. For example, a brief loss of the timing reference during the most recently completed PTP history bin could mark the OprOch field invalid for that one bin while every other bin around it remains fully trustworthy.