Bug: `C-h P' doesn't work for installed packages when Emacspeak is active

[Lubos Pintes <lubos.pintes@xxxxxxxxxxx>]

Hello,
I just noticed that when Emacspeak is running, and I issue a describe 
package, for example
`C-h P adoc-mode <RET>', the following error appears:
Wrong type argument: integer-or-marker-p, #("20150524.909" 0 12 (button 
(t) category default-button face link follow-link t action #[257 
"\301\300!\207" [[cl-struct-package-desc adoc-mode (20150524 909) "a 
major-mode for editing AsciiDoc files in Emacs" ((markup-faces (1 0 0))) 
single "melpa" nil ((:url . 
"https://github.com/sensorflo/adoc-mode/wiki";) (:keywords "wp" 
"asciidoc")) nil] describe-package] 3 "

(fn BUTTON)"] ...))

This works fine for built-in package and also when I disabled Emacspeak.
Anyone able to reproduce it?