The input devices settings (for extended input, e.g. tablet) have changed some time ago to a different format. Now, I can set the stylus device to Screen to have it pressure sensitive as expected, and it is also stored as this in the preferences.xml, but on reload if forgets this setting.

My stylus device is called Stylus0, the eraser Eraser0. Setting the eraser to screen mode, in the preferences.xml I see something like

<group keys=";;;;;... axes="x;y;pressure;xtilt;ytilt;wheel" mode="screen" id="E:Eraser0" />

but no such entry for stylus or Stylus0 exists and is created...