diff --git a/src/Database/SqlPreprocessor.php b/src/Database/SqlPreprocessor.php
index dcaad0ca1..000f29454 100644
--- a/src/Database/SqlPreprocessor.php
+++ b/src/Database/SqlPreprocessor.php
@@ -97,7 +97,6 @@ public function process(array $params, bool $useParams = false): array
 
 			if (($this->counter === 2 && count($params) === 2) || !is_scalar($param)) {
 				$res[] = $this->formatValue($param, self::MODE_AUTO);
-				$this->arrayMode = null;
 
 			} elseif (is_string($param) && $this->counter > $prev + 1) {
 				$prev = $this->counter;
@@ -197,7 +196,7 @@ private function formatValue($value, string $mode = null): string
 		if ($mode && is_array($value)) {
 			$vx = $kx = [];
 			if ($mode === self::MODE_AUTO) {
-				$mode = $this->arrayMode;
+				$mode = $this->arrayMode ?? self::MODE_LIST;
 			}
 
 			if ($mode === self::MODE_VALUES) { // (key, key, ...) VALUES (value, value, ...)
@@ -226,10 +225,10 @@ private function formatValue($value, string $mode = null): string
 				}
 				return '(' . implode(', ', $kx) . ') VALUES (' . implode(', ', $vx) . ')';
 
-			} elseif (!$mode || $mode === self::MODE_SET) {
+			} elseif ($mode === self::MODE_SET) {
 				foreach ($value as $k => $v) {
-					if (is_int($k)) { // value, value, ... OR (1, 2), (3, 4)
-						$vx[] = is_array($v) ? '(' . $this->formatValue($v, self::MODE_LIST) . ')' : $this->formatValue($v);
+					if (is_int($k)) { // value, value, ...
+						$vx[] = $this->formatValue($v);
 					} elseif (substr($k, -1) === '=') { // key+=value, key-=value, ...
 						$k2 = $this->delimite(substr($k, 0, -2));
 						$vx[] = $k2 . '=' . $k2 . ' ' . substr($k, -2, 1) . ' ' . $this->formatValue($v);
diff --git a/tests/Database/SqlPreprocessor.phpt b/tests/Database/SqlPreprocessor.phpt
index 02fe938e8..db3385e4f 100644
--- a/tests/Database/SqlPreprocessor.phpt
+++ b/tests/Database/SqlPreprocessor.phpt
@@ -332,7 +332,7 @@ test(function () use ($preprocessor) { // insert
 	[$sql, $params] = $preprocessor->process(['/* comment */  INSERT INTO author',
 		['name' => 'Catelyn Stark'],
 	]);
-	Assert::same(reformat("/* comment */  INSERT INTO author [name]='Catelyn Stark'"), $sql); // autodetection not used
+	Assert::same(reformat("/* comment */  INSERT INTO author 'Catelyn Stark'"), $sql); // autodetection not used
 	Assert::same([], $params);
 });
 
@@ -440,10 +440,10 @@ test(function () use ($preprocessor) { // update
 	Assert::same([12, 'John Doe'], $params);
 
 
-	[$sql, $params] = $preprocessor->process(['UPDATE author SET a=1,',
+	[$sql, $params] = $preprocessor->process(['UPDATE author SET a=1,', // autodetection not used
 		['id' => 12, 'name' => 'John Doe'],
 	]);
-	Assert::same(reformat('UPDATE author SET a=1, [id]=?, [name]=?'), $sql);
+	Assert::same(reformat('UPDATE author SET a=1, ?, ?'), $sql);
 	Assert::same([12, 'John Doe'], $params);
 });