Playback Acting Up

Hi! For the orchestra, I'm making a piece - I put the Oboes to play a C4 (because they play a C5 in the previous passage). The C5 note is absolutely fine, but for the C4, it's playing a B3 back. I'm 100% the note is right (on middle C), and it's all at concert pitch. Every other instrument playing this note is fine. What should I do?

TLDR: Oboe playback is off, but only for C4 (plays B3 instead).