Yet more info and a better fix:

xinput list --long provides this for the device:

⎜   ↳ GN Netcom A/S Jabra EVOLVE LINK MS      	id=15	[slave  pointer  (2)]
	Reporting 16 classes:
		Class originated from: 15. Type: XIButtonClass
		Buttons supported: 12
		Button labels: "Button 0" "Button 1" "Button 2" "Button Wheel Up" "Button Wheel Down" "Button Horiz Wheel Left" "Button Horiz Wheel Right" "Button 3" "Button 4" "Button 5" "Button 6" "Button 7"
		Button state:
		Class originated from: 15. Type: XIKeyClass
		Keycodes supported: 248
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 0:
		  Label: Abs X
		  Range: 0.000000 - 1000.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 1600.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 1:
		  Label: Abs Y
		  Range: 0.000000 - 1000.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 900.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 2:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 3:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 4:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 5:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 6:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 7:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 8:
		  Label: Abs Misc
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 9:
		  Label: Abs MT Touch Major
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 10:
		  Label: Abs MT Touch Minor
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 11:
		  Label: Abs MT Width Major
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 12:
		  Label: Abs MT Width Minor
		  Range: 0.000000 - 12.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000
		Class originated from: 15. Type: XIValuatorClass
		Detail for Valuator 13:
		  Label: None
		  Range: -1.000000 - -1.000000
		  Resolution: 0 units/m
		  Mode: absolute
		  Current value: 0.000000


Since it is reporting 12 potential buttons, I just mapped them all to zero by putting the following into /usr/share/X11/xorg.conf.d/50-jabra.conf:

Section "InputClass"
	Identifier "Jabra"
        MatchProduct "GN Netcom A/S Jabra EVOLVE LINK MS"
	Option "ButtonMapping" "0 0 0 0 0 0 0 0 0 0 0 0"
EndSection


Now the mouse pointer works properly and the volume buttons on the USB audio device work properly.

It would be great if this could be added to something like /usr/share/X11/xorg.conf.d/10-quirks.