[p2t2p]

why would I have this hostname? It is random string with letters and numbers as usual. A container-per-build, never heard about it?

[_whiteCaps_]

Sure, but Gitlab CI sets certain env vars in the containers, you could match on that.

[hsbauauvhabzb]

This, some antivirus sandboxes use similar heuristics also.

[ryanbrunner]

Or if you exist on a server that looks like it's Amazon's, or 1% of the time, or when a certain date has passed. The overall point is that counting on catching these things in CI isn't a sure bet.