(originally reported https://www.wikidata.org/wiki/Wikidata:Report_a_technical_problem/WDQS_and_Search#WDQS_wikibase:around_issue)

It might happen that in some circumstances a wikibase:around is ignoring exact matches.
For instance Q5637175 has point equals to Point(-2.5307 53.0268) but searching for this exact same location the query service is unable to find it:

SELECT DISTINCT ?item ?itemLabel ?location ?dist WHERE 
{
  SERVICE wikibase:around {
    ?item wdt:P625 ?location.
    bd:serviceParam wikibase:center "Point(-2.5307 53.0268)"^^geo:wktLiteral.
    bd:serviceParam wikibase:radius "0.1".
    bd:serviceParam wikibase:distance ?dist.
 }
 SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Varying the searched point a bit (e.g. Point(-2.5307 53.02681)) the point is found.

It is unclear why this happens, might be some bug (edge cases) in how the search spaces is approximated with a surrounding box?