Index: trunk/src/org/openstreetmap/josm/data/imagery/WMTSTileSource.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/imagery/WMTSTileSource.java	(revision 18567)
+++ trunk/src/org/openstreetmap/josm/data/imagery/WMTSTileSource.java	(revision 18568)
@@ -615,5 +615,5 @@
         // Java has issues if spaces are not URL encoded. Ensure that we URL encode the spaces.
         if (layer.format.contains(" ")) {
-            layer.format = layer.format.replace(" ", "&20");
+            layer.format = layer.format.replace(" ", "%20");
         }
         return layer;