If you are connected to 2.4GHz wifi, and connect a bluetooth mouse, the mouse seems to lose bandwidth, skipping around the screen when moving. If you toggle wifi off and on again, the issue goes away. If you connect the Bluetooth device AFTER wifi is connected, it works fine.
As I understand, this is a Dell-branded Broadcomm radio.
XPS 15 9550
Dell wireless 1830 BT 4.1 LE w/new Surface arc mouse