The non-standard join can use a numeric value, rather than a column or string constant. This behavior is regressed. The likely cause of this regression is new delimiting support for schema elements introduced in JPA 2.0. The constant column value used to be detected during schema definition based on the assumption of the name being enclosed in single-quote. Due to introduction of delimiting capability, the constant value is now enclosed in double-quote followed by a single-quote.
While the string constant (single quote) has been fixed, the numeric constant (would not have single quote) is still broken.
The visible effect is failure to define schema for non-standard join with constant NUMERIC values.