I have noticed that Onkelos switches his translation of ivri from sefer Bereishis where he exclusively translates ivri as a variation on עבראי\עברי and throughout the rest of chumash where he uses יהודאי\יהודיתא (except for the translations regarding eved ivri for which he uses "yisroel.")
Why the difference? I ask the question with particular reference to the very contradictory vacillation between the end of sefer Bereishes and the beginning of Shemos where the use of 'ivri' in both is in the context of direct speech by an Egyptian.