No, that is why we use the “test for null / set to null” trick in rules to see if the timer exists or not.
Bear in mind while developing rules, if your timer code executes but has an error it will never get to the variable=null assignment. The timer’s handle variable does not return to null by itself any other way.
The “fix” is to reload your rules file, which will also reinitialize your timer handle variable to null.
