diff --git a/parso/python/diff.py b/parso/python/diff.py
index 396dc9e..f901813 100644
--- a/parso/python/diff.py
+++ b/parso/python/diff.py
@@ -578,8 +578,14 @@ class _NodesTree(object):
 
         Returns the number of tree nodes that were copied.
         """
-        if tree_nodes[0].type == 'error_leaf' and tree_nodes[0].token_type == 'INDENT':
-            # Avoid copying error indents. Just parse them again.
+        i = 0
+        for i, n in enumerate(tree_nodes):
+            if tree_nodes[0].type not in ('INDENT', 'DEDENT'):
+                break
+
+        if tree_nodes[i].type in ('error_leaf', 'error_node'):
+            # Avoid copying errors in the beginning. Can lead to a lot of
+            # issues.
             return []
 
         self._get_insertion_node(tree_nodes[0])
@@ -622,10 +628,6 @@ class _NodesTree(object):
 
             new_nodes.append(node)
 
-        while new_nodes and new_nodes[0].type == 'error_leaf' \
-                and new_nodes[0].token_type in _INDENTATION_TOKENS:
-            new_nodes.pop(0)
-
         if not new_nodes:
             return [], working_stack, prefix
 
diff --git a/test/test_diff_parser.py b/test/test_diff_parser.py
index 93014e0..9accde8 100644
--- a/test/test_diff_parser.py
+++ b/test/test_diff_parser.py
@@ -205,7 +205,7 @@ def test_open_parentheses(differ):
     differ.parse(new_code, parsers=1, expect_error_leaves=True)
 
     new_code = 'a = 1\n' + new_code
-    differ.parse(new_code, copies=1, parsers=1, expect_error_leaves=True)
+    differ.parse(new_code, parsers=2, expect_error_leaves=True)
 
     func += 'def other_func():\n pass\n'
     differ.initialize('isinstance(\n' + func)
@@ -502,7 +502,7 @@ def test_endmarker_newline(differ):
     code2 = code1.replace('codet', 'coded')
 
     differ.initialize(code1)
-    differ.parse(code2, parsers=1, copies=2, expect_error_leaves=True)
+    differ.parse(code2, parsers=2, copies=1, expect_error_leaves=True)
 
 
 def test_newlines_at_end(differ):
@@ -1099,7 +1099,7 @@ def test_all_sorts_of_indentation(differ):
                 end
         ''')
     differ.initialize(code1)
-    differ.parse(code2, copies=2, parsers=3, expect_error_leaves=True)
+    differ.parse(code2, copies=1, parsers=4, expect_error_leaves=True)
     differ.parse(code1, copies=1, parsers=3)
 
     code3 = dedent('''\
@@ -1127,4 +1127,24 @@ def test_dont_copy_dedents_in_beginning(differ):
         ''')
     differ.initialize(code1)
     differ.parse(code2, copies=1, parsers=1, expect_error_leaves=True)
-    differ.parse(code1, copies=1, parsers=1)
+    differ.parse(code1, parsers=2)
+
+
+def test_dont_copy_error_leaves(differ):
+    code1 = dedent('''\
+        def f(n):
+            x
+            if 2:
+                3
+        ''')
+    code2 = dedent('''\
+        def f(n):
+        def if 1:
+                indent
+            x
+            if 2:
+                3
+        ''')
+    differ.initialize(code1)
+    differ.parse(code2, parsers=1, expect_error_leaves=True)
+    differ.parse(code1, parsers=2)