You have a custom interface between Rally and Clarity that sends hours from Rally into Clarity that has been working for a number of years. Recently, after the upgrade to v15.9.3, a few time entries for some tasks have come over as split time. That is, some tasks have two entries of equal number of hours in the same timesheet. Is this a known issue with the new version?
Release : 15.9.3
Issues related to non-Broadcom Clarity / Rally integrations aren't supported. So far we have not had any reports of this type of issue. The recommendation would be to test again after you switch to the out-of-the-box Clarity-Rally interface. If it does still happen then, open a case with Broadcom support requesting assistance.