diff --git a/src/graphnet/data/dataconverter.py b/src/graphnet/data/dataconverter.py
index 54cbbf418..616030ae1 100644
--- a/src/graphnet/data/dataconverter.py
+++ b/src/graphnet/data/dataconverter.py
@@ -580,19 +580,17 @@ def _filter_mask(
             frame: I3Frame to check.
             I3filters: List of I3Filters to check for pass.
         """
-        if "FilterMask" in frame:
-            for filter in I3filters:
-                if filter in frame["FilterMask"]:
-                    if frame["FilterMask"][filter].condition_passed is False:
-                        return True
-                else:
-                    self.warning_once(
-                        f"Filter {filter} not found in frame. Skipping filter check."
-                    )
-                    continue
-        else:
+        if "FilterMask" not in frame:
             self.warning_once(
                 "FilterMask not found in frame. Skipping filter checks."
             )
             return False
+        for filter in I3filters:
+            if filter not in frame["FilterMask"]:
+                self.warning_once(
+                    f"Filter {filter} not found in frame. Skipping."
+                )
+                continue
+            if frame["FilterMask"][filter].condition_passed is False:
+                return True
         return False