By comparing the xml files exported by Microsoft Project and ProjectLibre respectively, I investigated the cause of error in loading the xml file, exported by ProjectLibre, to Microsoft Project.
As a result, there is something wrong with the data generation of the part of "Assignments".
The date and time used to assign the work time to the task seems different from what it should be.
For this reason, the apparent duration is shortened because work hours, that should be evenly distributed, are allocated at a certain time period concentratedly.
Is it possible to ask for correction on this matter?