I am using pega 7.1.8 .

I am facing issue with some tasks that goes missing from the case .It's instances are also not found in the assign-worklist nor in assign-workbasket class.

It is not fixed that the task assigned to worklist goes missing or the tasks assigned to the workbasket goes missing.Then we have to manually repair assignment to bring them back.

I've checked the pxAssignmentkey , but in my application its stored in pr_other and is not exposed. 

Can anyone help on how can I fix it?

Thanks in advance.