you can double check to see if it's a reported bug or not
I think this might be because if you touch slightly up or down it overrides the left and right
other than vibration, which is not within it's scope
the 'custom controls' plugin has a much less buggy version of the 360 plugin
plus you don't need to set up multiple conditions for multiple control schemes
but back to your cap
this line will do all the 360 analog stuff, and also take into account the analogness of it:
click the image for full view