I'm on phpBB 3.2.3, but i assume not change the scenario.
As on my test Mark, still the patch not work.
Assuming that i'm still on 3.2.9, i've by the way applied patches just replacing files (assuming on 3.2.10 nothing change on db about this) but the result is:
$checked_forums = $this->request->variable('forums', array(''));still empty and also
$all_forums = $this->request->variable('all_forums', $this->user->data['user_digest_filter_type']);return empty value.
So these vars aren't passed where need to be and the code not fire at same point noted before.
I've see on fly changes done into ext/phpbbservices/digests/styles/all/template/js/digests.js file:
since all js scripts fire onclick, i've not understand why when onmouseover when in ucp -> Digests -> Forums selection, where option Include posts for these forums:, the console return
Empty string passed to getElementById()
it seem something you've forget somewhere on code, that so lead after to not grab and assign correctly vars to be passed?
May it is some test code i've leave around, i'll check as soon.