Workaround:
The issue is caused by the MajorTickInterval property, so one way to go is to remove this setting and use the LabelInterval instead. This will plot more ticks than before, but should eliminate the label clip. If the number of ticks bothers you, you can set the MajorTickLength property of the axis to 0 (so that the ticks are not visible) and use a LabelTemplate in which you will include a label and a tick. 

Another, simpler, work-around is to set a right margin of the chart and set the ClipToBounds property of the chart to false.