arduino leonardo stops transmitting once hdmi cable is connected to a screen
The issue is that the mouse coordinates are being set by the display device that it's attached to.
The computer sends a descriptor about the display to the HID device ( the mouse ) the mouse then uses the information about the logical size of the screen to co-ordinate the movements.
For example, to move with Mouse.move(100,100,0); you are not actually moving by 100 pixels, but by 100/(127-((-127)).
The only option is can suggest is to STOP the mouse and Restart it again - this will be easier to restart calculations again.
Heres my Logic Function to convert Percentage to appropriate values for Mouse.move();
int percentToLogic(int percent) { return percent*254/100; }