If there is evidence - and that can include credible testimony from witnesses in a position to know - that there is was an established protocol in place for informing new employees or employees in general about how to make elections and change elections and there is no evidence of the employee attempting to make an election, then it's the employee's unsubstantiated claim vs. that evidence. I would see no material risk of disqualification in that scenario, and an equally low risk that the employee would prevail in court on some type of damages claim.