Over the last couple of months, I've noticed that a lot of workers in the service industry including cashiers, drive-thru restaurant cashiers, servers at drive-thrus and others have started to say "my pleasure" whenever I say "thank you."

It only started a couple of months ago that this was widespread.

Yes, I heard "my pleasure" before -- the phone operators at Caesars Palace in Las Vegas always said "my pleasure" when you called and asked for a department or person:

"Hi, can have restaurant reservations please?"
"Connecting, my pleasure."

But now it seems everyone is doing it.

Has there suddenly been a wave of new training for service workers about how to say "my pleasure"?

It is such a different response from what I am used to, that it really stands out.