I think what's going on there is that one of the e-cigs they used had a configurable temperature (200-600 °F). I'll give them the benefit of the doubt and assume that they selected a reasonable one (they don't appear to specify in the methods).

Separately, there's the GC-MS machine - oven (30 - 220 °C ramp) and inlet (320 °C). This shouldn't be (much of) an issue though, as an inert carrier gas is used. Plus you always have controls, so if the GC-MS itself is tearing things apart it should hopefully be obvious.

That being said, I didn't see anything particularly concerning listed in their results (relative to recreational cigarette or alcohol consumption).