I would guess someone outside the FV system, with more experience working with TSSAA and transfers, knew about it all along but waited to turn it in until the end because either
1. Just malicious (or personal grudge) which is sad to think but there are those people. Unfortunately.
2. They Had something to gain. Playoff positioning would be most obvious but there could be something else or another angle.
The "why" is less important at this point than the learning experience IMO. Its done, let it go and hopefully don't repeat it again (although it seems likely someone, somewhere will).