diff --git a/masque/utils/ports2data.py b/masque/utils/ports2data.py
index b67fa0a..b97b41e 100644
--- a/masque/utils/ports2data.py
+++ b/masque/utils/ports2data.py
@@ -160,13 +160,17 @@ def data_to_ports_flat(
 
     local_ports = {}
     for label in labels:
-        name, property_string = label.string.split(':')
-        properties = property_string.split(' ')
-        ptype = properties[0]
-        angle_deg = float(properties[1]) if len(ptype) else 0
+        if ':' not in label.string:
+            logger.warning(f'Invalid port label "{label.string}" in pattern "{pstr}" (missing ":")')
+            continue
+
+        name, property_string = label.string.split(':', 1)
+        properties = property_string.split()
+        ptype = properties[0] if len(properties) > 0 else 'unk'
+        angle_deg = float(properties[1]) if len(properties) > 1 else numpy.inf
 
         xy = label.offset
-        angle = numpy.deg2rad(angle_deg)
+        angle = numpy.deg2rad(angle_deg) if numpy.isfinite(angle_deg) else None
 
         if name in local_ports:
             logger.warning(f'Duplicate port "{name}" in pattern "{pstr}"')