When you invoke a custom module with unordered params and the URL ends with a slash, the slash is not removed from the value.

Invoke URI /mymodule/myview/(myparam)/test/

The Value of $Param['myparam'] will result in "test/". When you add more params, like /mymodule/myview/(myparam)/test/(mysecondparam)/test2, the trailing slash will be removed properly.

This behavior seems to have changed between eZ-Publish 4.x and 5.x, which looks like a BC break.