"However, it appears the 4/15 payment was bumped out to 6/15 as the IRS had it scheduled for that date. We obviously cancelled that 6/15 payment because the client made the failed Q1 estimate."

Yes, that's why you read the links given as replies.

Intuit explained the combining of the Estimates; the IRS explained the late payment date for the returns.

There are Two Parties involved with these mistakes and delays. Reading the notifications, from the links, helps you know what actions to take and what not to bother doing.