I had this on one of the DBR races - I was dropped from a group and this rider caught me up pushing exactly 3.4 w/kg. No deviation all the time he was chasing me (lump or descent) and when he caught me he didn't punch etc to get past me. I sat on his wheel for a while at about 2.8 w/kg and he was pulling me along ... not a jot of deviation. As this was a race, and I suspected it was a bot, I dropped my power to let him pull away so I didn't get an unfair advantage. I called it out on the race, but it didn't stop the guy further up the road I was chasing to then sit on the bot's wheel and stop me from catching himI cycled along with a guy the other day. I was going in and around 3w/kg. His power stuck to 3w/kg without deviation for as long as I was looking at it. It did make me wonder if he was a cyborg. Or maybe he just had an incredibly smooth and consistent pedal stroke.
Not seen the bot in any other DBR races so maybe someone else called him out.