I flew that exact plane for a while. During the short time I was there DS had an engine failure in that tail number. I'd be very surprised that it was just a single engine issue. They handled SE fairly well even with freight on board.

Speculation Warning!!! Maybe things changed since I flew there but I never heard of anyone actually getting deiced at APA while I was there. KLA did supply a small ice scrapper and some rags though. Not saying DS would fly a plane with air frame contamination but it could explain why the airplane was not able to hold altitude on one engine.