Worklist item could not be opened. 26030 Worklist item 4803_21 not found for K2:DOMAINAccountName at 10.10.10.10:2276

I wonder if somebody have this issue when a  copy of the User Task Email goes to the originator and then he open the Form prior to the Approver, seems like it lock the workflow.

how can this be prevented and perhaps just not lock the workflow until the supervisor approve it.

THX DIno