Ummm yeah...no. READ what the OP stated. The OP was a misconnect, so obviously there was at least one.

In 12 years of flying DL 150 times a year, Ive never once had VIPR remove my original segment (before the connecting flight was closed out in DLmatic which is after it's in the air). I have had it add additional segments, but never had it remove an active one where I had a chance to connect. I've made 10 minute connections (due IROPS) more than a few times. This is not to say it can't happen, I've just never experienced it, but then again, I monitor my connections like a hawk.

It sound like the OP had ample time, but they were unchecked in for some unknown reason. DL can see exactly who or what did that, but it's not likely they'd share that with pax anyway.