Is the redirect property stale cached data?
Were these pages redirects?

All these pages are listed at special page [1] and the last update was done today. The sample page 11 فبراير wasn't changed since 5 weeks and is not a redirect.[2] Maybe it was a redirect previously [3]. The redirect was broken after deletion [4] but become a normal page afterwards.

I've no glue how to fix it. Neither purge nor null edit nor a small edit [5] does change the special page entry.

[1] https://ar.wikipedia.org/wiki/%D8%AE%D8%A7%D8%B5:%D8%AA%D8%AD%D9%88%D9%8A%D9%84%D8%A7%D8%AA_%D9%85%D9%83%D8%B3%D9%88%D8%B1%D8%A9
[2] https://ar.wikipedia.org/wiki/11_%D9%81%D8%A8%D8%B1%D8%A7%D9%8A%D8%B1
[3] https://ar.wikipedia.org/w/index.php?title=%D8%AE%D8%A7%D8%B5%3A%D8%B3%D8%AC%D9%84&type=move&user=&page=11+%D9%81%D8%A8%D8%B1%D8%A7%D9%8A%D8%B1&year=&month=-1&tagfilter=
[4] https://ar.wikipedia.org/w/index.php?title=%D8%AE%D8%A7%D8%B5%3A%D8%B3%D8%AC%D9%84&type=delete&user=&page=11+%D9%81%D8%A8%D8%B1%D8%A7%D9%8A%D8%B1&year=&month=-1&tagfilter=
[5] https://ar.wikipedia.org/w/index.php?title=5_%D8%AF%D9%8A%D8%B3%D9%85%D8%A8%D8%B1&type=revision&diff=19023011&oldid=18946489

@Anomie Why have these pages a namespace 105 property if this ns does no longer exist?

In T130915#2154997, @Xqt wrote:

@Anomie Why have these pages a namespace 105 property if this ns does no longer exist?

As far as MediaWiki is concerned, a namespace is just a semi-arbitrary number and any number "exists". But if the namespace doesn't have any name configured, various things will break (e.g. pages in the namespace won't be finable in many usual ways, and trying to construct a title for these pages will give nonsensical results as seen here) due to lack of a name mapping for the namespace number.

It's similar to the reverse problem when a new namespace is created (or when bugs like T87645 happen), a page exists in the default namespace but can't be accessed in the usual ways because its title now refers to a page in a different namespace.

I've asked a local sysop for deleting these pages because I've no sysop account at ar-wiki. Patches for pywikibot are in review now. Thanks a lot for your kind attention you gave this matter.

Note: I reported the problem of wrong results being shown on arwiki's Special:BrokenRedirects in T127459 You may wish to merge the two tasks.

In T130915#2155558, @Xqt wrote:

I've asked a local sysop for deleting these pages because I've no sysop account at ar-wiki. Patches for pywikibot are in review now. Thanks a lot for your kind attention you gave this matter.

I deleted the pages through the API as Xqt descriped (Check my deletion log) and ar:Special:BrokenRedirects looks clean right now.

Thanks Meno25!