No, I did not, as I was mostly noodling with different routes and fares. As I stated, it was bookable through Kayak; but if I wanted to use pay with miles, that avenue was not going to be available. I encountered this issue (bookable through Kayak, but not able to reproduce using multi-city on DL.dumb) on several different itineraries.

I was curious is anyone else had noticed this issue. If I had to, I would call. Apparently, one more step DL wants me to take in their effort to provide a seamless customer-friendly experience.