diff --git a/zerver/lib/bugdown/__init__.py b/zerver/lib/bugdown/__init__.py
index f1a9382283..669fa3ae14 100644
--- a/zerver/lib/bugdown/__init__.py
+++ b/zerver/lib/bugdown/__init__.py
@@ -902,12 +902,11 @@ class Bugdown(markdown.Extension):
                 if k not in ["autolink"]:
                     del md.inlinePatterns[k]
             for k in md.treeprocessors.keys():
-                if k not in ["inline_interesting_links"]:
+                if k not in ["inline_interesting_links", "inline", "rewrite_to_https"]:
                     del md.treeprocessors[k]
             for k in md.preprocessors.keys():
-                del md.preprocessors[k]
-            for k in md.postprocessors.keys():
-                del md.postprocessors[k]
+                if k not in ["custom_text_notifications"]:
+                    del md.preprocessors[k]
             for k in md.parser.blockprocessors.keys():
                 if k not in ["paragraph"]:
                     del md.parser.blockprocessors[k]
diff --git a/zerver/test_bugdown.py b/zerver/test_bugdown.py
index ee1299e6aa..ba290187ff 100644
--- a/zerver/test_bugdown.py
+++ b/zerver/test_bugdown.py
@@ -386,4 +386,10 @@ class BugdownTest(TestCase):
             converted,
             "<p>* test</p>",
             )
+        msg = "https://lists.debian.org/debian-ctte/2014/02/msg00173.html"
+        converted = bugdown.convert(msg, "mit.edu/zephyr_mirror")
+        self.assertEqual(
+            converted,
+            '<p><a href="https://lists.debian.org/debian-ctte/2014/02/msg00173.html" target="_blank" title="https://lists.debian.org/debian-ctte/2014/02/msg00173.html">https://lists.debian.org/debian-ctte/2014/02/msg00173.html</a></p>',
+            )