diff --git a/classes.py b/classes.py
index d514da9..c963d9d 100644
--- a/classes.py
+++ b/classes.py
@@ -1223,6 +1223,10 @@ class PyLinkNetworkCoreWithUtils(PyLinkNetworkCore):
                 log.debug("(%s) reverse_modes: skipping reversing '%s %s' with %s since it "
                           "wasn't previously set.", self.name, char, arg, mpair)
                 continue
+            elif mpair in newmodes:
+                # Check the same for regular modes that previously didn't exist
+                log.debug("(%s) reverse_modes: skipping duplicate reverse mode %s", self.name,  mpair)
+                continue
             newmodes.append(mpair)
 
         log.debug('(%s) reverse_modes: new modes: %s', self.name, newmodes)
diff --git a/test/protocol_test_fixture.py b/test/protocol_test_fixture.py
index b50b5d5..fe8409a 100644
--- a/test/protocol_test_fixture.py
+++ b/test/protocol_test_fixture.py
@@ -761,4 +761,29 @@ class BaseProtocolTest(unittest.TestCase):
         out = self.p.reverse_modes('#weirdstuff', '-b+b *!*@* *!*@*')  # -+ cycle existing ban
         self.assertEqual(out, '-b *!*@*')  # Ugly but OK
 
+    def test_reverse_modes_cycle_arguments(self):
+        # All of these cases are ugly, sometimes unsetting modes that don't exist...
+        c = self.p.channels['#weirdstuff'] = Channel(self.p, name='#weirdstuff')
+
+        out = self.p.reverse_modes('#weirdstuff', '+l-l 30')
+        self.assertEqual(out, '-l')
+        out = self.p.reverse_modes('#weirdstuff', '-l+l 30')
+        self.assertEqual(out, '-l')
+
+        out = self.p.reverse_modes('#weirdstuff', '+k-k aaaaaaaaaaaa aaaaaaaaaaaa')
+        self.assertEqual(out, '-k aaaaaaaaaaaa')
+        out = self.p.reverse_modes('#weirdstuff', '-k+k aaaaaaaaaaaa aaaaaaaaaaaa')
+        self.assertEqual(out, '-k aaaaaaaaaaaa')
+
+        c.modes = {('l', '555'), ('k', 'NO-PLEASE')}
+        out = self.p.reverse_modes('#weirdstuff', '+l-l 30')
+        self.assertEqual(out, '+l 555')
+        out = self.p.reverse_modes('#weirdstuff', '-l+l 30')
+        self.assertEqual(out, '+l 555')
+
+        out = self.p.reverse_modes('#weirdstuff', '+k-k aaaaaaaaaaaa aaaaaaaaaaaa')
+        self.assertEqual(out, '+k NO-PLEASE')
+        out = self.p.reverse_modes('#weirdstuff', '-k+k aaaaaaaaaaaa aaaaaaaaaaaa')
+        self.assertEqual(out, '+k NO-PLEASE')
+
     # TODO: test type coersion if channel or mode targets are ints