For mirror mode it's another problem, we gotta set the reaction time to 100ms (default is 1000ms) which is far too slow. Sadly this affects every script but it's not really a problem, it's just the way the client is designed to protect memory usage ^^ Think of that option like ping/latency in gaming for example, it takes 1000ms (1 second) to realise the tree has been cut.
Solution is top-right of client (click cogs button, 4th option down): turn off recommended settings, slide to 100 and it should be optimised.
With that being said, we scripters have the option to automatically set this to 100ms (if the [allow script override] button is enabled), which is what I'll do in v86.0 shortly. Update coming up.
in the meantime while we wait, please tell me how it goes I'm eager to know I'll be here to help always. I personally always set it to 100ms when using mirror, unless I wanna afk.