Setup:

Build a nether portal and start punching it in survival by holding left click. While punching the portal, go through it while still holding down left click. Once you go through, you are no longer punching the portal (or any other blocks you might be facing), even though you're still holding down left click.

Expected Behaviour:

You would continue to punch blocks until you release left click, even when you move between dimensions.

Alternative Demonstrations:

• This also occurs with right click, which can be tested by giving the player a stack of honey bottles. In survival, stand in the portal and start drinking the honey bottles - the player will stop drinking once they get sent through the portal.
• It also occurs with any other actions custom bound to a mouse button - for instance, if you bind the Move Forward action to a mouse button and using it to move through a portal in creative mode, you will stop moving the moment you go through the portal, until you release and re-press the mouse button.