diff --git a/tidy3d/components/base.py b/tidy3d/components/base.py
index 0db64c656f..5733cab445 100644
--- a/tidy3d/components/base.py
+++ b/tidy3d/components/base.py
@@ -887,7 +887,7 @@ def check_equal(dict1: dict, dict2: dict) -> bool:
                     return False
 
                 # convert tuple to dict to use this recursive function
-                if isinstance(val1, tuple) or isinstance(val2, tuple):
+                if isinstance(val1, tuple) and isinstance(val2, tuple):
                     val1 = dict(zip(range(len(val1)), val1))
                     val2 = dict(zip(range(len(val2)), val2))