Problem
Users are unable to specify a redirect page for a partial block because the redirects are resolved to pages in the Pages field.
https://it.wikipedia.org/w/api.php?action=query&prop=info%7Cpageprops&generator=prefixsearch&gpssearch=1%20dicembre&gpslimit=10&ppprop=disambiguation&redirects=true
Solution
Remove the redirects option from the API query:
https://it.wikipedia.org/w/api.php?action=query&prop=info%7Cpageprops&generator=prefixsearch&gpssearch=1%20dicembre&gpslimit=10&ppprop=disambiguation
which should allow users to specify the redirected page.