Index: core/units/helpers/deployment_helper.php
===================================================================
--- core/units/helpers/deployment_helper.php
+++ core/units/helpers/deployment_helper.php
@@ -396,22 +396,26 @@
 			return false;
 		}
 
-		foreach ($matches as $index => $match) {
-			$revision = $match[1][0];
+		$revision_numbers = array();
 
-			if ( $this->revisionApplied($revision) ) {
-				// skip applied revisions
-				continue;
-			}
+		foreach ( $matches as $index => $match ) {
+			$revision = $match[1][0];
 
-			if ( isset($this->revisionSqls[$revision]) ) {
-				// duplicate revision among non-applied ones
+			if ( in_array($revision, $revision_numbers) ) {
+				// Duplicate revision among non-applied ones.
 				$this->displayStatus('FAILED' . PHP_EOL . 'Duplicate revision #' . $revision . ' found');
 
 				return false;
 			}
 
-			// get revision sqls
+			$revision_numbers[] = $revision;
+
+			if ( $this->revisionApplied($revision) ) {
+				// Skip applied revisions.
+				continue;
+			}
+
+			// Get revision sqls.
 			$start_pos = $match[0][1] + strlen($match[0][0]);
 			$end_pos = isset($matches[$index + 1]) ? $matches[$index + 1][0][1] : strlen($sqls);
 			$revision_sqls = substr($sqls, $start_pos, $end_pos - $start_pos);