Why would you enable a timer that is already enabled in the first place?

>I have a container with a TIMER that has the INTERVAL set to 1 minute. It is ENABLED (or disabled) in the REFRESH of the container. That refresh is visited each 10 seconds.
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>I noticed that the timer did no longer fire each minute if its ENABLED.property is explicitly set to True each 10 seconds.
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>It does fire if I only set the ENABLED property if its new value differs from the current value.
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>It seems as though the ENABLED property acts as some sort of RESET().
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>Who can explain this? Or do I miss a clue?