Post Election error when Evaluating Life Event

Summary:

A life event ( Divorce ) occurred after open enrollment period is ended. We wanted to process the intervening life event (occurred in Nov/Dec ). This should ideally backout the closed open life event to unprocessed state, when processed . However we are encountering the Post election edit FF error

"There was a problem saving the enrollment. The formula returned the message Election to HSA - Health Savings Account requires enrollment
in Medical HDHP.. If you're a benefits administrator, note that the enrollment result didn't satisfy the post election edit rules that
were defined in the formula. Review the formula, make changes if required, and try again"