https://beta.musicbrainz.org/search?page=16&query=alice&type=artist&limit=25&method=indexed currently says there are 378 results.
https://beta.musicbrainz.org/search?page=17&query=alice&type=artist&limit=25&method=indexed says there are none.

If you're on page 17 and some entities are merged/removed (resulting in only enough results for 16 pages) and then you refresh, you'll get this behaviour, which is what happened to me.