Trying with latest host gives for me
; filamentDiameter=3
; filamentDiameter0=3
; filamentDiameter1=1.75
; filamentDiameter2=3
; Filament gcode
Which is correct. Not sure what you did wrong. But make sure to use . and not , for numbers. Slic3r uses , to separate the values in the list so wrong usage might confuse the slicer resulting in wrong values.
You also could look into the resulting slic3r_settings.ini in host workdirectory used for slicing. In may case you find
filament_density = 0
filament_diameter = 3,1.75
filament_max_volumetric_speed = 0
filament_notes = ""
Which is what you need to get the wanted result.