See ANSI SQL-92 section 8.2 part 7b) which describes this situation.
Using comparison operators with embeddables has essentially the same semantics as RVEs/RVCs in SQL.
Therefore the NOT EQUAL predicate must obey the rule as defined

"x <> Ry" is true if and only if RXi <> RYi for some i.

Which effectively means that OR is required.
This is still a problem in hibernate 5 and in my opinion a serious bug!