What specifically isn't working? This often comes up with anecdotes about Cakewalk, the suggestion to not use the forum search, but no specifics are given as whether or not there really is an issue here. I find it odd.
A few months back we did correct an issue with our search index that was limiting recent results in sub-forums, however this has been resolved.
The mobile theme, by design, seems to limit the page results intentionally so you're not waiting for days on a slow connection. If I search "Site Search", I get quite a lot of results including this thread, but only 3 pages displayed by default. Towards the bottom there are additional filters and page buttons.
I agree the forum software's mobile theme isn't really the most elegant thing to use, but I guess I'm just wondering why everyone's default response is that it's broken. Am I the only one that finds it odd?