Sherlockkat reported this as a possible bug via chat (see attached image).
I've determined the cause, a side effect of the system that allows larger maps to start up faster by delaying AI initialization. Unlike other bots, Researchers don't set their proper alignment until their first turn, so for a moment they will appear yellow if you entered the floor with active long-range sensors.
This is fine since you probably want to be more aware of their nearby starting locations anyway
Just posting it here to have this record (and let others know).