Hi the support locked the other thread as resolved but it WAS NOT RESOVLED. He misunderstood the issue.
The problem isn’t the dongle light going off when you turn the mouse off it’s the light on the mouse. Before the update on the v3 pro and on the DAV v3 and viper v2 pro - even the signature (I have them all on my desk) when you held the button to turn the mouse off the indicator ON THE MOUSE would flash to show it is turning off. Since the update on the v3 nothing happens with the light ON THE MOUSE when turning it off so you don’t know if it has switched off or not - you just have to hold the button for a bit and hope it does.
as this has happened to multiple people it’s clearly a bug in the firmware - the indicator light works when turning the mouse ON or switching DPI.