I've never had such issues. Have you tried a different browser?
One possible explanation that comes to mind - you can access Touch properties (X, Y, acceleration, angle etc.) only when the screen is actually in touch. Or if you are using mouse to emulate touch - when the left mouse button is pressed.
So, for example, this code will not work, because Touch.X,Y will become 0 after the wait:
On tap gesture -> Wait 0.1 seconds ; Set Sprite position to Touch.X, Touch.Y
When you are using Mouse plugin, you can track mouse X,Y all the time, no need to press any buttons.