I am sure my original problem was convex because it originated from the typical convex problem listed in the book “Convex Optimization”
No, no, no. This is not a reasonable justification. Prove it is convex, and then let’s talk. Until you do I am tagging this as Nonconvex. We cannot deal with problems whose authors cannot prove convexity. Do read the FAQ, there are actually technical reasons why this must be so.
You say that this is a “simplified” dual. One other suggestion is to back out some of those simplifications. Perhaps it was one of those simplifications that broke DCP structure.