Hi.
Its Possible that v22 is not yet on the asset store.
When you update an asset unity has to review it 1st and that can take some time (usually 1-2 weeks)
Playmaker can not slow the computer itself.
Also prefab in your project should not slow things down.
But if you have many fsms on an object and have it selected it can slow down due to unity's refresh system.
Also fsm's with a large amount of states can slow down.
You can collapse the fsm's in the inspector to reduce the lag for that.
Also in preferences there are some options that you can set.
But i don't really have issues with mouse going slow/freeze.
What does happen is if writing text or selecting and dragging states / actions that it becomes laggy.
I am sure that Alex is looking into it, but i also think that it not that simple to fix.
Else it would have been fixed already