Query worked fine using Hibernate 4.2.10
Query borked using Hibernate 4.2.12
query in question:
delete from com.mrbear.Transactionrelation trel where trel.timeperiod = :TIMEPERIOD and trel.krlObject = :OBJECT and not exists ( select '' from com.mrbear.Taxationtransaction tatr where tatr.transactionrelation.transactionRelationNr = trel.transactionRelationNr )

The problem disappears when I rename :OBJECT to :KRLOBJECT.

It is possible that OBJECT is a keyword in HQL and not allowed to be used, but why then did it work in the previous version of Hibernate (4.2.10)?

I hope you can reproduce it.