Ingenuity and Perseverance turn on their comm systems and talk during certain pre-determined periods of the day (e.g., at the top of the hour), to conserve power. Ingenuity initiates the call.
For this to work, both systems need to have "wall-clocks" (i.e., the date/time counter) whose values match closely.
Since Ingenuity's clock got reset and restarted due to the low power condition, the times when Ingenuity and Perseverance attempted to communicate with each other no longer matched.
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