Employer was not updating participants deferral changes they made on the Recordkeeper website. The plan is 3% Safe harbor, so no matching to worry about.
So if a plan missed updating a deferral for all of 2016 and 2017, do they to do any corrective remedies? Participant believed they were deferring 8% Roth, but the payroll was only deferring 7%. Basically $15 per pay period difference.
Is the link below relevant, or does it not apply because these are Roth contributions?
https://www.irs.gov/retirement-plans/fixing-common-plan-mistakes-correcting-a-failure-to-effect-employee-deferral-elections