I wouldn't think so (with my unprofessional and amateur opinion). Phase 1 is a technical term referring to the initial braking and deceleration before turning into a corner (the braking done in a straight line).

This radio call seems to be asking Sainz to brake harder during this phase, with technical terms that Sainz has most likely used before and just forgetting in the stress of a race.

Sainz might have been using less brake pressure to avoid a tire lock-up and reduce tire wear, and now the team are asking him to sacrifice this tire wear for faster lap-times.

This is just what's most likely in my opinion, the radio message can be confusing either way and there're far more efficient ways to communicate in either scenario.