Premiere Rush only recognising 5 seconds of a longer video

Hello,

I've been trying to add an 8 minute long, 4k MOV file into my project, but Rush is persistently telling me that it's only five seconds long. This is really confusing as the video is definitely 8 minutes long when played in QuickTime player (Mac). Also, the file properties still say that there are eight minutes of footage. Is there anything that can be done to fix this?

Thanks,

Olly