diff --git a/includes/CommentParser.php b/includes/CommentParser.php
index 4a511ec23..1b6dde777 100644
--- a/includes/CommentParser.php
+++ b/includes/CommentParser.php
@@ -922,7 +922,8 @@ class CommentParser {
 				$curCommentEnd = $node;
 			} elseif ( $node instanceof Text && ( $match = $this->findTimestamp( $node, $timestampRegexps ) ) ) {
 				$warnings = [];
-				$foundSignature = $this->findSignature( $node, $lastSigNode );
+				$foundSignature = $this->findSignature( $node,
+					$curCommentEnd === $this->rootNode ? null : $curCommentEnd );
 				$author = $foundSignature['username'];
 				$lastSigNode = $foundSignature['nodes'][0];
 
diff --git a/modules/Parser.js b/modules/Parser.js
index 7b653061e..1686f82bc 100644
--- a/modules/Parser.js
+++ b/modules/Parser.js
@@ -895,7 +895,8 @@ Parser.prototype.buildThreadItems = function () {
 			curCommentEnd = node;
 		} else if ( node.nodeType === Node.TEXT_NODE && ( match = this.findTimestamp( node, timestampRegexps ) ) ) {
 			var warnings = [];
-			var foundSignature = this.findSignature( node, lastSigNode );
+			var foundSignature = this.findSignature( node,
+				curCommentEnd === this.rootNode ? null : curCommentEnd );
 			var author = foundSignature.username;
 			lastSigNode = foundSignature.nodes[ 0 ];