distribution of over-deposited deferrals - options?

I see that we've discussed several issues relating to "overpayments" in this forum, but they seem to be focusing on employer contributions and incorrect allocations.

What about where the plan sponsor deposits too much into the deferral bucket (bad math, or whatever), and the participant takes their immediate distribution.  No other participants were harmed, and I'd argue that the plan doesn't have to be "made whole" because that money shouldn't have been in there in the first place.  Is this just a 'send a letter and if you get the money back, that's great' situation?

Thanks.

Mercer has a decent article, secure 2.0 had some stuff about this.

https://www.mercer.com/en-us/insights/law-and-policy/correcting-retirement-plan-overpayments-under-secure-2-0/