Unable to save custom settings tab after 3.x

[cyberwombat]

I have a few plugins w custom settings tab that stopped saving after upgrading Woo. I can see that the woocommerce_update_options_XXX and woocommerce_settings_save_XXX actions are firing from tapping into the WC code but for some reason this does not trigger any of the corresponding add_action in my plugins. My code is derived from this sample (at bottom) but that no longer works.

Any idea what WC change happened that might cause this? The actions are firing fine for loading the settings page but not saving.