Had one guy 2km’s (but only 12 seconds) behind a few weeks back!
Interesting you picked up on the August update - I too noticed strangeness with drafting and distances since that update and theirs loads of anecdotal evidence around various forums of the same.
I reckon a lot of these are related but possibly totally wrong. One thread of a quite a few that have mentioned, distances, drafting etc and gets occasional updates is this one for your ref.
I’d strongly suggest you log a ticket with support attaching a log file and the screen shots of the evidence to help them troubleshoot, as I have.