diff --git a/src/Psalm/Internal/FileManipulation/FunctionDocblockManipulator.php b/src/Psalm/Internal/FileManipulation/FunctionDocblockManipulator.php
index 931b9c5ab..011c10cdb 100644
--- a/src/Psalm/Internal/FileManipulation/FunctionDocblockManipulator.php
+++ b/src/Psalm/Internal/FileManipulation/FunctionDocblockManipulator.php
@@ -2,6 +2,7 @@
 namespace Psalm\Internal\FileManipulation;
 
 use PhpParser;
+use function array_shift;
 use function count;
 use function ltrim;
 use PhpParser\Node\Expr\ArrowFunction;
@@ -336,7 +337,10 @@ class FunctionDocblockManipulator
                     $doc_parts = CommentAnalyzer::splitDocLine($param_block);
 
                     if (($doc_parts[1] ?? null) === '$' . $param_name) {
-                        $modified_docblock = true;
+                        if ($param_block !== $new_param_block) {
+                            $modified_docblock = true;
+                        }
+
                         $param_block = $new_param_block;
                         $found_in_params = true;
                         break;
@@ -350,7 +354,14 @@ class FunctionDocblockManipulator
             }
         }
 
-        if ($this->new_phpdoc_return_type) {
+        $old_phpdoc_return_type = null;
+        if (isset($parsed_docblock['specials']['return'])) {
+            $old_phpdoc_return_type = array_shift($parsed_docblock['specials']['return']);
+        }
+
+        if ($this->new_phpdoc_return_type
+            && $this->new_phpdoc_return_type !== $old_phpdoc_return_type
+        ) {
             $modified_docblock = true;
             $parsed_docblock['specials']['return'] = [
                 $this->new_phpdoc_return_type
@@ -358,7 +369,15 @@ class FunctionDocblockManipulator
             ];
         }
 
-        if ($this->new_phpdoc_return_type !== $this->new_psalm_return_type && $this->new_psalm_return_type) {
+        $old_psalm_return_type = null;
+        if (isset($parsed_docblock['specials']['psalm-return'])) {
+            $old_psalm_return_type = array_shift($parsed_docblock['specials']['psalm-return']);
+        }
+
+        if ($this->new_psalm_return_type
+            && $this->new_phpdoc_return_type !== $this->new_psalm_return_type
+            && $this->new_psalm_return_type !== $old_psalm_return_type
+        ) {
             $modified_docblock = true;
             $parsed_docblock['specials']['psalm-return'] = [$this->new_psalm_return_type];
         }