The mouse cursor disappears when running on Macbook Pro plugged in external 4k Display.
The same happens with a fresh install.
My Sublime version:
Here a video that a recorded to demonstrate.
Also I found a clue about what is going on.
When using the 4k scaled them mouse cursor vanish.
However, when using 1920x1080 which is doubled pixels, it works great.
It is annoying not been possible to code as I like using a scaled resolution