This may be out in left field, but I’ve seen similar symptoms in other parts of the tool that were cause by a couple things. First, un-aligned calendars. For example, the Standard project calendar work days are 8-12 and 1-5 but some of the resource calendars are set to work days of 8-4. Additionally, I’ve seen this occur when the Calendars don’t match the default hours/day set in the Options. For example, the default Day = 8, but calendars indicate a different value such as 7.5 or 9. In this scenario, the durations were being entered as 4D meaning the D value was controlled by the default Days duration and not the resource calendar. Like I said, it’s a long shot.