No. During schedule changes, it's very common for a flight to be cancelled and then recreated (sometimes with a different flight number or a different aircraft). Usually that's pretty seamless, but sometimes the rescheduling system is too fast and tries to be helpful by rebooking people before the flight gets recreated. The system is often dumb and unhelpful, but it's not malicious and it's not trying to make money.

If you booked thru DL, they'd fix it for you without any problem. But you'll have to go thru your travel agent instead, hopefully they should be just as accommodating but who knows.