Check to see if it actually captured at 25 fps.
I’ve had this problem before. Or at least something that sounds similar.
Unfortunately I haven’t figured out a real good solution for it. I think it’s an issue with the compatibility between premiere and that camera. The JVC GY-HD100, right?
I at least troubleshot it down to it not being captured at the correct frame rate at times. It only happened occasionally. The video would move at regular speed but the audio would be fast. And my only solution thus far is to make sure to capture within the boundaries of when you turned on the camera for the shot and when you turned it off. So don’t start the capture before a cut at the beginning of the capture period, and don’t go over a cut for the end.
My theory is that for a split second when the camera was off, even if you wrote timecode to the tape already before shooting, the camera defaults back to 60i. I have no idea why… but the theory is based off one of the original problems the camera had which had to be patched a long time ago. It used to always default to DV and would constantly flash something like “change to DV 1394” when you had it set to capture HDV footage.
Anyway, if anyone knows why this is otherwise and how to fix it feel free to comment back, but the best way I’ve worked around the problem is capturing between cuts.