A timer running means it is currently executing the code inside its timer block. This event will usually only last a few milliseconds, and you’d be (un)lucky to catch it when your rule retriggers.
A timer active means that the timer is currently counting down.
You may want to check whether your timer is active, rather than running.
Check the draft reference here.
(I also first thought that running meant that the timer was counting down - “the timer is running” in common parlance would usually suggest the same. I would have preferred executing and running instead of the current running and active respectively, but there’s history here!)