Percent versus double dollar parent context reference

[asalabaev]

on try.jsonata.org the following expression is used to access the parent and the grandparent contexts: Account.Order.Product.{ 'Product': Product Name, 'Order': %.OrderID, 'Account': %.%.Account Name }

However in java (version 0.9.9) the percent symbol has no effect and instead the double dollar $$ should be used Account.Order.Product.{ 'Product': Product Name, 'Order': $$.OrderID, 'Account': $$.$$.Account Name }

I am logging it as a bug since the readme has a statement that All JSONata language features supported and a link reference chain to the try.jsonata.org site. If it is not a bug please shed some light on this notations difference. I was not able to find the explanation.