@Arshad8101 We have last stage as Resolution Stage with Checkbox checked to complete all open assignments. It is a child case. Actually we have two or more child cases created. For only one child case this issues happens. Other child cases is resolved-completed with same process.
@Arshad8101 I have traced. In pxForceCaseClose - At Step 11 pzUpdateAndDeleteAssignments activity is called and Case status is Resoved-Completed. Step 12 Begin- It is changed to "New". I don't see any lock issues.