Well. We could see this as them having a bit of a hard time pretending to be a normal comet, but ultimately showing just enough signs to convince us humans that they are one... I guess?

They are just venting all their pee tanks

Don't be sad, there's still a chance it hits Earth and ends human civilization!

Comet 3I/ATLAS is an interstellar comet currently traversing the solar system.

Probably observing the trajectory