There's nothing that suggests that Merc broke any rules. Bottas did a lap time of 2:07.440 which looks comparable to other drivers. There is a minimum time they're supposed to set, but that's all. So long as Lewis slows sufficiently, and Bottas doesn't slow in a dangerous fashion there's nothing to investigate. Max was also making comments about not being within 10 car lengths, but the drivers have to reach the lead driver first before forming up and when they did reach him they were clearly within 10 car lengths.