This is not a bug. The reason your pulse extender is acting like a clock is because you did not power it for long enough. For example, if you use 2 comparators in the pulse extender, then powering it for 1 tick will cause it to act like a clock, while powering it for 2 or more ticks will cause it to act like a pulse extender. Make sure you are powering the pulse extender for long enough so that every comparator becomes powered before you unpower it.
Gabriel Steele
This is not a bug. The reason your pulse extender is acting like a clock is because you did not power it for long enough. For example, if you use 2 comparators in the pulse extender, then powering it for 1 tick will cause it to act like a clock, while powering it for 2 or more ticks will cause it to act like a pulse extender. Make sure you are powering the pulse extender for long enough so that every comparator becomes powered before you unpower it.