Please make sure that you are not using @GeneratedValue(strategy=GenerationType.SEQUENCE) - that would cause this error.
If you are using identity then use
@GeneratedValue(strategy=GenerationType.IDENTITY) instead.
I can't see how using @GeneratedValue(strategy=GenerationType.AUTO) may cause attempt to use sequence object SEQ_GEN_SEQUENCE, unless you define a SequenceGenerator named SEQ_GEN which uses sequenceName SEQ_GEN_SEQUENCE.
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