impdp ORA-01449: column contains NULL values; cannot alter to NOT NULL

Hello,

I have strange problem.

I'm importing schema by impdp statament, and following error occurs:

ORA-39083: Object type CONSTRAINT:"SCHEMA"."PK_TABLE" failed to create with error:

ORA-01449: column contains NULL values; cannot alter to NOT NULL

but this table does not contains any nulls in column which are included into PK...

any idea why it happen?

Thanks.

Best regards,

Mateusz