Same IV but transfered the highest cp =(

[Marwin]

[12:45:03] Caught Horsea CP(236) IV(51) successfully.
[12:45:03] Received 210 EXP.
[12:45:03] Received 100 stardust.
[12:45:03] Received 3x candy.
[12:45:06] Transfered Horsea with CP(435) IV(51) successfully.

why would it transfer the highest CP? when the IV is the same?