..

src/sia/models/sia_query_params.py

@@ -401,7 +401,7 @@ def to_butler_parameters(self) -> SIAv2Parameters:
             band=self.band or (),
             exptime=self.exptime or (),
             calib=self._convert_calib(calib=self.calib),
-            maxrec=self.maxrec,
+            maxrec=str(self.maxrec) if self.maxrec is not None else None,
         )
 
     @staticmethod