replacing display specification fails to preserve box around replaced text

[Jonas Bernoulli]

When replacing the text at the end of a region that has a face which
draws a box around that text, replacing text at the end of that region
using a display specification fails to preserve the box around the
replaced text. The box above and below the replaced text is shown as
expected though. At the beginning of the text all sides of the box are
shown as expeced.

(progn
  (insert (propertize "foo" 'face '((:box (:line-width 5 :color "red")))))
  (backward-char)
  (put-text-property (point) (1+ (point)) 'display "*"))

results in:
+---
|fo*
+---

(progn
  (insert (propertize "foo" 'face '((:box (:line-width 5 :color "red")))))
  (backward-char 3)
  (put-text-property (point) (1+ (point)) 'display "*"))

results in:
+---+
|*oo|
+---+

Both 22.1 and 23.0.60 behave this way.

-- Jonas