Abhas Mitra, On the non-occurrence of Type I X-ray bursts from the black hole candidates, Advances in Space Research, Volume 38, Issue 12, 2006, Pages 2917-2919, ISSN 0273-1177, 10.1016/j.asr.2006.02.074.
(http://www.sciencedirect.com/science/article/pii/S0273117706002523)
If I'm reading this correctly the answer to your question is yes, but the more specific details covered are more so the lack of specific xray signatures in explaining certain matter phenomena that point to QGP as a theoretical explanation.