Cron Task does not start at precise frequency

[Nexucis]

Based on user feedback, it appears the cron task is not starting at a precise frequency.

The issue appears when you are running a cron task every 5 minutes for example. Instead of starting every 5 seconds regardless the time it took to run it, it is running 5s + the time it took to run at previous time.

Example:

First run completed at 18:45:05 sec and next starts at 18:50:05 sec so the scheduler literally adds 5 mins to end time of previous execution

Note: This should be investigated (ideally by coding a test reproducing the issue)