diff --git a/core/database_api.php b/core/database_api.php
index fd2af58ed3..efaef42957 100644
--- a/core/database_api.php
+++ b/core/database_api.php
@@ -322,7 +322,12 @@ function db_query_bound( $p_query, $arr_parms = null, $p_limit = -1, $p_offset =
 		$lastoffset = 0;
 		$i = 1;
 		if( !( is_null( $arr_parms ) || empty( $arr_parms ) ) ) {
-			while( preg_match( '/(\?)/', $p_query, $matches, PREG_OFFSET_CAPTURE, $lastoffset ) ) {
+			while( preg_match( '/\?/', $p_query, $matches, PREG_OFFSET_CAPTURE, $lastoffset ) ) {
+				$matches = $matches[0];
+				# Realign the offset returned by preg_match as it is byte-based,
+				# which causes issues with UTF-8 characters in the query string
+				# (e.g. from custom fields names)
+				$matches[1] = utf8_strlen( substr( $p_query, 0, $matches[1]), mb_internal_encoding() );
 				if( $i <= count( $arr_parms ) ) {
 					if( is_null( $arr_parms[$i - 1] ) ) {
 						$replace = 'NULL';
@@ -346,10 +351,10 @@ function db_query_bound( $p_query, $arr_parms = null, $p_limit = -1, $p_offset =
 						echo( "Invalid argument type passed to query_bound(): $i" );
 						exit( 1 );
 					}
-					$p_query = utf8_substr( $p_query, 0, $matches[1][1] ) . $replace . utf8_substr( $p_query, $matches[1][1] + utf8_strlen( $matches[1][0] ) );
-					$lastoffset = $matches[1][1] + utf8_strlen( $replace );
+					$p_query = utf8_substr( $p_query, 0, $matches[1] ) . $replace . utf8_substr( $p_query, $matches[1] + utf8_strlen( $matches[0] ) );
+					$lastoffset = $matches[1] + utf8_strlen( $replace );
 				} else {
-					$lastoffset = $matches[1][1] + 1;
+					$lastoffset = $matches[1] + 1;
 				}
 				$i++;
 			}