diff --git a/stix2/test/test_versioning.py b/stix2/test/test_versioning.py
index dcbd3d3..233587e 100644
--- a/stix2/test/test_versioning.py
+++ b/stix2/test/test_versioning.py
@@ -223,8 +223,8 @@ def test_remove_custom_stix_property():
     mal_nc = stix2.utils.remove_custom_stix(mal)
 
     assert "x_custom" not in mal_nc
-    assert stix2.utils.parse_into_datetime(mal["modified"], precision="microsecond") < stix2.utils.parse_into_datetime(mal_nc["modified"],
-                                                                                                                       precision="microsecond")
+    assert stix2.utils.parse_into_datetime(mal["modified"], precision="millisecond") < stix2.utils.parse_into_datetime(mal_nc["modified"],
+                                                                                                                       precision="millisecond")
 
 
 def test_remove_custom_stix_object():
diff --git a/stix2/utils.py b/stix2/utils.py
index 3129a5c..701fe56 100644
--- a/stix2/utils.py
+++ b/stix2/utils.py
@@ -303,7 +303,14 @@ def remove_custom_stix(stix_obj):
         # add to set the custom properties we want to get rid of (with their value=None)
         props.extend(custom_props)
 
-        return new_version(stix_obj, **(dict(props)))
+        new_obj = new_version(stix_obj, **(dict(props)))
+
+        while parse_into_datetime(new_obj["modified"]) == parse_into_datetime(stix_obj["modified"]):
+            # Prevents bug when fast computation allows multiple STIX object
+            # versions to be created in single unit of time
+            new_obj = new_version(stix_obj, **(dict(props)))
+
+        return new_obj
 
     else:
         return stix_obj