sphinxsearch, possible missed EscapeString for keywords

When search keywords contains // simbols, for example ".... http:// ....." get search error:

index index_phpbb_...._delta,index_phpbb_...._main: syntax error, unexpected '/' near '//'

After adding EscapeString function from /includes/sphinxapi.php to file /phpbb/search/fulltext_sphinx.php search returned normal result, found all ".... http:// ...."

open /phpbb/search/fulltext_sphinx.php
find

		$result = $this->sphinx->Query($search_query_prefix . str_replace('"', '"', $this->search_query), $this->indexes);

before add

		$this->search_query = $this->sphinx->EscapeString($this->search_query);

But it is not correct way, because operator NOT (simbols -, !) was escaped by this function.
How to fix it? Or may be it is not bug?..