(Note: I marked this as a Major because my user community often needs to search for hyphenated strings, and it is difficult to educate the entire user base that they need to not use hyphens in the search string.)

For the complete (but short) thread: https://www.phpbb.com/community/viewtopic.php?f=46&t=2167421

But, to put the relevant information here:

If I search for "attributes match" in my phpBB, the search correctly locates posts that contain the string "attributes-match". However, if I search for "attributes-match", the following is reported:

No posts were found because the word attributes-match is not contained in any post.

The search backend doesn't seem to treat the hyphenated string as two words, in the sense that searching for "attributes match" and "attributes-match" do not return the same results. The first does find posts that contain "attributes-match", but the second does not.

To summarize:
1) Searching for "attributes match" returns posts that contain "attributes", "match" and "attributes-match".
2) Searching for "attributes-match" does not return any posts.

Thanks!
pkas1