diff --git a/grammar.js b/grammar.js
index 10e8ea8c..e56bf9c5 100644
--- a/grammar.js
+++ b/grammar.js
@@ -119,7 +119,7 @@ module.exports = grammar({
     identifier: _ => _identifier_rules(false),
 
     long_flag_identifier: _ =>
-      token.immediate(/[0-9\p{XID_Start}_][\p{XID_Continue}?_-]*/u),
+      token.immediate(/[0-9\p{XID_Start}_][\p{XID_Continue}?._-]*/u),
 
     _command_name: $ =>
       choice(
diff --git a/script/known-failures.txt b/script/known-failures.txt
index b4fd207a..585ccfe9 100644
--- a/script/known-failures.txt
+++ b/script/known-failures.txt
@@ -21,6 +21,7 @@ examples/nu_scripts/custom-completions/pytest/pytest-completions.nu
 examples/nu_scripts/custom-menus/current_session_history_menu.nu
 examples/nu_scripts/example-config/init.nu
 examples/nu_scripts/make_release/gen-ts-ext.nu
+examples/nu_scripts/make_release/twin-tweaks.nu
 examples/nu_scripts/make_release/notes/tools.nu
 examples/nu_scripts/modules/duplicates/example.nu
 examples/nu_scripts/modules/kubernetes/complete.nu
diff --git a/src/grammar.json b/src/grammar.json
index 42d3dfb8..0b9bcbbc 100644
--- a/src/grammar.json
+++ b/src/grammar.json
@@ -1787,7 +1787,7 @@
       "type": "IMMEDIATE_TOKEN",
       "content": {
         "type": "PATTERN",
-        "value": "[0-9\\p{XID_Start}_][\\p{XID_Continue}?_-]*",
+        "value": "[0-9\\p{XID_Start}_][\\p{XID_Continue}?._-]*",
         "flags": "u"
       }
     },
diff --git a/src/parser.c b/src/parser.c
index a8402ce2..df971450 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -10698,7 +10698,7 @@ static const TSCharacterRange sym_long_flag_identifier_character_set_1[] = {
 };
 
 static const TSCharacterRange sym_long_flag_identifier_character_set_2[] = {
-  {'-', '-'}, {'0', '9'}, {'?', '?'}, {'A', 'Z'}, {'_', '_'}, {'a', 'z'}, {0xaa, 0xaa}, {0xb5, 0xb5},
+  {'-', '.'}, {'0', '9'}, {'?', '?'}, {'A', 'Z'}, {'_', '_'}, {'a', 'z'}, {0xaa, 0xaa}, {0xb5, 0xb5},
   {0xb7, 0xb7}, {0xba, 0xba}, {0xc0, 0xd6}, {0xd8, 0xf6}, {0xf8, 0x2c1}, {0x2c6, 0x2d1}, {0x2e0, 0x2e4}, {0x2ec, 0x2ec},
   {0x2ee, 0x2ee}, {0x300, 0x374}, {0x376, 0x377}, {0x37b, 0x37d}, {0x37f, 0x37f}, {0x386, 0x38a}, {0x38c, 0x38c}, {0x38e, 0x3a1},
   {0x3a3, 0x3f5}, {0x3f7, 0x481}, {0x483, 0x487}, {0x48a, 0x52f}, {0x531, 0x556}, {0x559, 0x559}, {0x560, 0x588}, {0x591, 0x5bd},
diff --git a/test/corpus/pipe/commands.nu b/test/corpus/pipe/commands.nu
index 45622d9e..a91083cd 100644
--- a/test/corpus/pipe/commands.nu
+++ b/test/corpus/pipe/commands.nu
@@ -217,6 +217,8 @@ cmd-010-long-flag
 ======
 
 cmd --long-flag --42
+# issue 249
+curl --tlsv1.2
 
 ------
 
@@ -227,6 +229,13 @@ cmd --long-flag --42
         (cmd_identifier)
         (long_flag
           (long_flag_identifier))
+        (long_flag
+          (long_flag_identifier)))))
+  (comment)
+  (pipeline
+    (pipe_element
+      (command
+        (cmd_identifier)
         (long_flag
           (long_flag_identifier))))))