The Lightroom CC getting started tutorial states that the default setting on the radial gradient tool is to apply the adjustments 'outside' the 'radial'. If you want the adjustment to apply 'within' the 'radial' you would click 'invert'.
However, on my version (4.2) the default setting is to apply the changes within the radial, and if I click 'invert' the changes apply outside the radial. I've been unable to locate where I can adjust the default setting for the radial gradient tool.
Can anyone help or explain why my tool is acting in the opposite to what's described/demonstrated in the tutorial?
I believe the 'invert' setting is a "sticky". ie. if you change it once, then each time you re-use the tool it should be in the 'invert' mode as you used it last. So there really is no 'default' mode, it is - how you leave it!
With tools like these your settings are 'sticky' if you apply them before you apply the tool itself. So if you select the gradient, check 'invert', and then apply the gradient, then 'invert' should be checked the next time you select the tool. If you first apply the tool and then check 'invert', then that will be considered as a one time action for this particular image only.