How do you properly use "Fetch entity by id" in Rules in order to access its fields?
I got to this question whilst searching for a different solution to my own problem, but I think I know what's wrong anyway, even if it's 2 years old, it might help someone in the future :P

I think you have to add a condition to determine the type of Entity you are looking at, either by using 'Entity has field' or 'Data comparison' to determine what content type you are looking at. The reason you only see the 'normal properties' by which I assume you mean NID, Author, Title etc, is because it cannot guarantee it has the fields you want, until you determine what content type it is