I've been trying to rework the regex patterns for search to be more accurate, provide for more edge cases and exclude instances where the search term is just in link and not the actual post text but it's tricky. Consequently, I've (temporarily) broken hashtag searches — I only noticed that last night after posting a new #acid track.
Rather than a straight search on the text in the database I was trying to process the markdown and then strip out HTML tags but something has gone wrong somewhere. It's complicated by the way I run two queries - one to identify the number of items found to set up the results paging and then one to actually return the results.
I'm going to revert back to the original queries and rethink how I'm doing it. I may just have to settle for a non-perfect solution that catches most items.