I'm using the com.sencha.gxt.chart.client.chart.Chart class with LineSeries.
When I'm presenting the yAxis on the left, the last value of the chart is cut.
This also happens when I add the yAxis both on the right and on the left.
However, when I add the yAxis on the right, the values are presented correctly (See screenshots at: https://www.dropbox.com/sh/f6hmjsj1k463ua1/JF2KDMZ0En).
Note that the data and all other configurations are exactly the same.
Looking at your screen shots it might be a text alignment issue for the axis labels. What version of GXT are you using? There were some text alignment issues in 3.0 that now have been resolved in 3.0.1.