Thank you for the reply.

Jump to the conclusion first: I can 100% confirm that it is the issue caused by the UEFI firmware or the aggregator firmware, the reason was that:

1. I have eliminated all the other factors which may causing this issue, including resetting/restoring the system, clean installation, update any software/driver available etc...

2. the problem was never there before the firmware update.

3. all the mice tested have no problem at all on any other desktop/laptop except the surface book 2 with the 389 version firmware

4. the other (second one) surface book 2 with the 388.1932.769.0 firmware had no problem but problem started to appear immediately right after the firmware updated to 389.2268.769.0 and aggregator firmware updated.

So the issue here is that I cannot revert back to the 388 version firmware anymore if there is no update provided by Microsoft.

Speaking about the issue itself, yes G703 mouse is a gaming mouse. Switching to the other Microsoft touch explorer mouse made the freeze/lag frequency lower but it still happens. When using the wireless mode of the G703, the mouse freeze/lag at random manner and frequency. But when using the wired mode (connecting to the surface book 2 using the usb cord), the mouse will totally freeze after a while even though the LED on the mouse is still on (meaning that the mouse is still physically connected but just not working).

Adjusting the power option from "recommended" to "better performance" make the problem worse, and "best performance" basically kills the mouse as it will freeze/lag almost every second.

At the moment, such update makes the device to be very hard to use. I hope there is a way to revert the firmware back to 388 version as this is the fastest way to solve the problem. (as a matter of fact, the latest driver package downloaded from Microsoft now has the 388 version included, not 389 anymore, even though 389 is still mentioned on the update history page).