Tasks on my project are changing unexpectedly from 'Completed' to 'Not Started'. (Another symptom noticed may be that the task % Complete is changing from 100% to 0% when using MSP)
One cause of this issue is due to a setting in MSP not being set to the recommended setting in working with Clarity PPM.
Release : All Supported Releases
Component : CA PPM SAAS MICROSOFT PROJECT (MSP)
1. Make sure 'Updating Task Status Updates Resource Status' is unchecked in MSP->File->Options->Schedule
2. Make sure 'Calculate project after each edit' is set to On in MSP->File->Options->Schedule