Roth in document, but not offered right away

[John Feldt ERPA CPC QPA]

Suppose a plan document was drafted and executed to allow both pre-tax and Roth deferrals, but the sponsor wasn't ready to handle Roth yet internally so the initial enrollment materials did not show that Roth was even available, but the SPD did describe Roth. About 3 months after the plan had been in effect, they communicated that the Roth deferral option was not available to the participants. What do eligible employee participants "get" or what is the correction?

[K2]

So I assume the plan's enrollment form and/or procedures didn't allow for a Roth election.  What would have happened had someone read the SPD and elected Roth?

Seems to me the best fix is to amend the plan and have the Roth effective date be the date it was truly effective.