The current mechanic for allowing MK to switch his place to end of his shard is by using auto cast feature. Why has it been done like that? Its very annoying and difficult to use right now.
So, currently to use this, you assign another key under AutoCast Key bindings. Then, when you want MK to move to end of his shaft you have to press that key, but doing so it sets the shaft to Autocast unless you disable it by pressing the key again. This is annoying as you have to press the key twice to make sure you moved to end of shaft, but it does not do so automatically again when you use the stun next time. But, this is annoying. You can mostly likely forget to disable the autocast after enabling it once in the heat of the battle.
Suggestion:
Temporarily enable another button and spell which allows MK to switch to end of his shaft. Like how it works for Void's Time Walk. I dont know why Developer got lazy with this and not just make another spell/button to switch MK to end of his shaft.
Valve please make this change. Upvote this post so it gets noticed please
Source: https://www.reddit.com/r/DotA2/comments/wycu3r/fix_monkey_king_shard_key_mechanism/