APEX-PDP engine metrics remain 0 even after execution of events

Metrics like pdpa_engine_uptime,pdpa_engine_average_execution_time_seconds, pdpa_engine_event_executions, pdpa_engine_last_start_timestamp_epoch counters are always 0 even after event executions.

They get incremented as soon as the event execution happens, but get reset 0 after sometime.

Also, pdpa_engine_last_execution_time_bucket, and pdpa_engine_last_execution_time_count keep on increasing by 1 every 2minutes even if no trigger events are there.