I haven't seen it, but would say that with my CI, following group conversation is much much easier. I would also venture that she is working incredibly hard to "track" individual voices as opposed to lipreading. Sometimes I have to cut my losses within a large group and pick two or three people to focus on. I also wonder whether she is very good at mirroring/echoing phrases eg "That was so funny" and she replies something like "Yeh, so funny!" Does this make any sense?
It is easier to float within banter and light conversation than to respond to direct and unpredictable questions.
I would also say she was very open at the start about her deafness so perhaps the contestants are being amazingly cool with it all.