FSA gets recalculated with subsequent life events

 I know this is a benefits issue, but I couldn't find that community.

Has anyone else encountered this issue? When we use the rate start code "First of Pay Period Preceding First Check On/After Event" for the open enrollment, we have found that all subsequent life events result in FSA elements getting recalculated.

The element entry stops and restarts (with a different amount) on the next day.

It also does not stop at the employee elected limit or the federal limit.

We do need to use the above said code, as we have part time employees whose pay period ends in the previous year, and check date is in the election year (jan)