This happened to me, only I was moved to the top of Varrock castle seemingly instantly, if there was a random even I do not know which one it was and did not see it for a moment. I was just killing a “man” in Lumbridge castle courtyard and it happened instantly out of nowhere.
I see that it indeed says that, just seems odd that I didn’t see anything at all, additionally, it says I failed one and was teleported, then 2 seconds I failed what is logged as another random event and my items were noted. Was this the same event you think? If not, 2 seconds seems like an awfully quick fail time.
I guess for now I will give the system the benefit of the doubt and say that I just didn’t see something, but I feel like there might be something going on. Like even the OP seemingly wasn’t afk, it reads as if they logged off, logged back in and had “failed an event”. Seems like possibly people are failing them without them appearing.
Ultimately I guess it’s not that big of a deal, just thought id put this follow up post out there.
I recommend enabling background recording with game capture, so that whenever something like this happens you can see what actually happened. That way you can also help with troubleshooting if you encounter a bug. But based on the adventure log you most likely just didn’t notice the npc. Playing with audio can help, as some (or all?) randoms play a sound when appearing.