I've upgraded a solution from the v8.2 to the v10.3 binaries and now my 3D Line charts have duplicate axis labels on all the axis. I can't find any setting to turn this off and comparing the VS 2008 to the VS 2010 properties for this chart they seem the same.
Have you tried to set the Visible property of the X2, Y2 and Z2 axes of your chart instance to false?
You can review the aspx source code of the following sample:
https://es.infragistics.com/samples/aspnet/chart/3d-chart-rotation
This fixed it. I find it strange that the 8.2 versions had the X2, Y2 and Z2 visible values set to true but did not show the extra legends.
Thanks.