If the vpn is running on the host, you’ll need to find out how to make custom routing rules on that operating system to ensure that it will not send those packets through the tunnel. That is out of scope for this forum in general because it actually has nothing to do with (and can’t be addressed by) openwrt.
But I’m glad you found the issue and that the firewall rules are working as expected.
If your problem is solved, please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.
Thanks! 