Do not try to escape the key string as this will not work with colons.
diff --git a/reclass/utils/dictpath.py b/reclass/utils/dictpath.py
index f5c4e36..0d23c96 100644
--- a/reclass/utils/dictpath.py
+++ b/reclass/utils/dictpath.py
@@ -122,10 +122,7 @@
             return []
 
     def new_subpath(self, key):
-        try:
-            return DictPath(self._delim, self._parts + [self._escape_string(key)])
-        except AttributeError as e:
-            return DictPath(self._delim, self._parts + [key])
+        return DictPath(self._delim, self._parts + [key])
 
     def get_value(self, base):
         return self._get_innermost_container(base)[self._get_key()]