The expression pictured above is used in the Order transactions table to find the price and date of the most recent sale to the registered customer. There is no problem with the expression and it gives the correct result.
However, it gives the following result when the text concatenation sign (&) is not used.
I don’t know if I have a known bug, I think it’s the fault of the expression assistant and the code block that compiles the expressions. For your information.