As mentioned, I'd forget about it as you can't know what he was on about. You mention he had a pillion, so for all you know he has an intercom with them and the pillion asked him a question to which he replied no and shook his head, which was at the time you passed and took it to mean he meant something you did wrong. If it's something technically wrong (from what you describe) you can filter to the front but you're not meant to 'overtake' the first vehicle (everyone does so don't worry about it and I think this is just pedestrian crossing, would need to check). If he's a bit of a do-gooder, which it he could be as you mention he was 4 cars back so maybe doesn't approve of filtering, then that could also be the case. Riding a bike sometimes involves bending the rules to stay safe. I always 'push' to the front if safe to do so, so that I can pull away quickly and avoid having to overtake that first car. Also they know you're there when they've got you stood in front of them.