I have a similar situation to you (Dependent e-filed first, I e-filed later - all information was correct identifying as dependent on his return).
I also received IND-517-01 and was certain my dependent filled it out correctly but he received an IND-452 error before I even e-filed, and upon filing again has continued to receive that error code. There's a possibility someone used his information for a fraudulent tax return, so we're looking into that, and this may not be the same situation but if you don't mind me asking, did your dependent also receive a rejection from the IRS when e-filing or did theirs get accepted and only yours is rejected?
