diff --git a/image_prediction/flask.py b/image_prediction/flask.py
index 7ab4005..b1473da 100644
--- a/image_prediction/flask.py
+++ b/image_prediction/flask.py
@@ -63,7 +63,7 @@ def make_prediction_server(predict_fn: Callable):
         logger.info("Analysing...")
         predictions = predict_fn_wrapped(request.data)
 
-        if predictions:
+        if predictions is not None:
             response = jsonify(predictions)
             logger.info("Analysis completed.")
             return response
diff --git a/image_prediction/image_extractor/extractors/parsable.py b/image_prediction/image_extractor/extractors/parsable.py
index a022396..9fe5b46 100644
--- a/image_prediction/image_extractor/extractors/parsable.py
+++ b/image_prediction/image_extractor/extractors/parsable.py
@@ -13,8 +13,11 @@ from image_prediction.image_extractor.extractor import ImageExtractor, ImageMeta
 from image_prediction.info import Info
 from image_prediction.stitching.stitching import stitch_pairs
 from image_prediction.stitching.utils import validate_box_coords, validate_box_size
+from image_prediction.utils import get_logger
 from image_prediction.utils.generic import lift
 
+logger = get_logger()
+
 
 class ParsablePDFImageExtractor(ImageExtractor):
     def __init__(self, verbose=False, tolerance=0):
@@ -162,7 +165,11 @@ def has_alpha_channel(doc, xref):
     if maybe_smask:
         return any([doc.extract_image(maybe_smask) is not None, bool(fitz.Pixmap(doc, maybe_smask).alpha)])
     else:
-        return bool(fitz.Pixmap(doc, xref).alpha)
+        try:
+            return bool(fitz.Pixmap(doc, xref).alpha)
+        except ValueError:
+            logger.debug(f"Encountered invalid xref `{xref}` in {doc.metadata.get('title', '<no title>')}.")
+            return False
 
 
 def tiny(metadata):
diff --git a/src/serve.py b/src/serve.py
index 005cbb2..57749b0 100644
--- a/src/serve.py
+++ b/src/serve.py
@@ -10,7 +10,6 @@ from image_prediction.utils.banner import show_banner
 
 
 def main():
-    logger = get_logger()
 
     def predict(pdf):
         # Keras service_estimator.predict stalls when service_estimator was loaded in different process;
@@ -26,7 +25,9 @@ def main():
 
 
 if __name__ == "__main__":
-    logging.basicConfig(level=CONFIG.service.logging_level)
+    logging.basicConfig()
+    logger = get_logger()
+    logger = logger.setLevel(CONFIG.service.logging_level)
 
     show_banner()