Missed Roth Contributions

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

Why would Roth contributions have an exception to a failure to implement deferrals?

Missed Roth deferrals are treated the same as missed pre-tax deferrals. See Rev. Proc. 2016-51, Appendix B, 1.03 for your situation and Appendix A .05(3) for an improper exclusion.