When an incident is re-assigned to another user or group the lease on the task isn't broken
This functionality is part of the design of the product. This functionality is in place to ensure that multiple users cannot work the same Ticket/Task at the same time. Symantec has investigated the possibility of changing the lease behavior particulary around Reassignment functionality in ServiceDesk and has determined that changing this behavior would have unintended consequences which would impact functionality and reliability.
There are two possible work arounds for this issue. Please note that changing either of these settings is a global change that affects leasing of every task. Disabling task leasing could lead to a situation where multiple users are attempting to work the same Ticket/Task at the same time.
Workflow Solution 7.5