You look away for a while and suddenly things have changed. This kind of thing is totally commonplace and not remarked upon. Getting on a bus comes with an obligation to be photographed and filmed to be seen not only by Transport for London, who run the buses, but also the rest of your fellow passengers.
When I remember, I try to sit near enough to the screen to be able to take a weird kind of selfie like this. It takes some co-ordination because the image is reversed and you have to take account of where the CCTV camera is as well as having your phone/camera not be to obtrusive. Ideally, I'd also be looking into the lens so that I don't look like I'm looking at the floor, but it's hard to keep the camera straight and release the shutter while looking in a completely different direction (up and to my right on this occasion).
I'm sure there's a lengthy and fascinating privacy policy somewhere that tells us how this information is used and how long it's retained for. I have a someday/maybe project that involves documenting a day walking around town with video and stills taken without my conscious knowledge on CCTV, retrieved via a series of (probably quite expensive) Data Subject Access requests.