Just so everyone knows our prior responses when this came up in the other thread, we have no doubt that there are no timing restrictions on eliminating the plan for 2019 in late 2018, even though SH notices were distributed. Austin is having trouble accepting that, but that doesn't change the situation, of which (on this one) I am certain.
Class year vesting was eliminated a long time ago - there was a discussion on that here within the last month or so.
The only way to do that would be to adopt a brand new plan every year and exclude service before the plan's effective date, but 4-year cliff still wouldn't be permitted, and I'm sure IRS would have big issues with this when they caught up with you anyway.
I don't think this could be corrected under VCP; as it really doesn't amount to an operational failure of the plan. Instead, it involves a failure of the payer to properly report the distributions.
Good Luck!
Oh my God make this effective 12/31/18. Someone botched that one in my opinion, and you have 3 days to fix it, can I get a "Hallelujah!" A day makes all the difference in the world in one sense (by eliminating even a shadow of doubt), and no difference at all in another sense (because really what practical/logistical difference does it make?).