They also detected tachyons, which they said may indicate time travel (and cloaking and other stuff), so the tachyons on top of the advanced technology to create the bursts, plus the exo-suit which implies not quite non-corporealness means possible time traveller here.
It's still way too much of a stretch for Michael, of all people, to almost definitively state it's a time traveller rather than other possibilities. This episode, of course, features a time rift and time tsunami and temporal distortions, and verified evidence that a probe was tampered with 500 years in the future, so they all should have a good idea that they're dealing with time travellers or maybe 4D species (like the Prophets or the guys Harry Mudd stole from).
Time travel really shouldn't be a thing until nine years later, although even in Archer's time, and untold adventures since, they should understand that other races have had temporal capabilities.
