The 10 degree bug occurs when you have a Honeycomb yoke.
Removing all buttons on the yoke is supposed to fix it.
Its a dreadful situation that good hardware is not supported correctly.
EDIT: This morning I removed all button assignments, except the hat switch, on my Honeycomb yoke.
The 10 degree step for SPD and HDG step reverted back to 1 degree steps, on the same A320nx flight stationary on the runway.