This may not be an issue introduced by your changes, but neither "(" nor ")" need to be quoted in query strings.  According to http://www.456bereastreet.com/archive/201008/what_characters_are_allowed_unencoded_in_query_strings/ these are the values that do not need to be quoted in query strings:

ALPHA / DIGIT / “-” / “.” / “_” / “~” “!” / “$” / “&” / “’” / “(” / “)” / “*” / “+” / “,” / “;” / “=” / “:” / “@” / “/” / “?” 

Also apparently pre-percent-encoded values don't need to be reescaped, although I'd probably ignore that, as folks expect the quoting to happen.