Either Lewis genuinely did not know what was going on and was confused... or more likely didn't know 100% but still had a good idea, but also didn't want to pass him before the DRS line... while Max absolutely did want him to pass before it and so slowed down even further.
Bit of a grey area as both essentially trying to achieve an advantage.. or not be disadvantaged by it depending on your POV.
Until I see telemetry I'm not sure its clear cut who was most at fault so I think I'd just settle for racing incident.. something to learn from and also tighten up the rules.

It reminds me of a similar-ish incident many years ago. Lewis being told to let someone (maybe Kimi?) pass at Spa iirc after achieving an off the track pass... but did so by positioning his car so that he could get a better exit and re-pass immediately.. which he did and subsequently was either told to let him pass again or was given a time penalty, can't remember which.