Missed Deferral Opportunity - with a twist

Hi, 

Our client contacted us to let us know that a participant completed a deferral election form November 2023 and they've been making deposits into her brokerage account.  However, the deductions were never set up with payroll.  She just noticed a year later.  

The client spoke with their payroll company and their labor lawyer and both said as long as they don't tell her it's required, she can sign something and can have deductions for the next 3 payrolls to make up for it.  The payroll person even mentioned her writing the company a check (I explained that the money shouldn't be from her, if would need to come from her SDBA if she were to pay it back).  

I explained to her they have two issues going on: 1. failure to implement and because of that 2. excess deposits.  I calculated a QNEC, g/l and the full safe harbor match and then figured out the difference between that and what was deposited. 

I guess I'm just looking for guidance because even with the deposits being made erroneously, I feel like this is still a MDO that needs to be corrected.  

This sounds like the plan's fine but her take-home pay was done wrong.