This is a issue in a 1.5.5 new game unmodded. When you first enter a village and check your Hero healing rate it shows a "in Settlement" bonus of +8, when you choose "wait here for some time" the bonus disappears. So one of the UI is bugged.
Before waiting, +19.7
While waiting +11.7, in settlement bonus of +8 is missing
Before waiting, +19.7