You’re welcome!
First and foremost, I would suggest you make sure your AUDIO FILE is at the SAME sample rate as your timeline settings for the specific fcp sequence where you are editing.
If your AUDIO FILE is at 48.000 hZ, your sequence should be the same.
If it is 44.100 hZ, so should be your sequence.
To check metadata on your AUDIO FILE, open it with Quicktime and press command+i – this should open a window with details about your AUDIO FILE.
Is your AUDIO FILE in WAVE format?
If so, you can import it to Wave Agent and check metadata there.
Than alter it to match your sequence settings in FCP.
Make sure you make a copy of your original AUDIO FILE BEFORE altering it with Wave Agent.
If not in WAVE format, convert it to WAVE and proceed to Wave Agent to alter frame rate to match your FCP sequence settings.
I really hope you can resolve this issue.