pfSense - PIA OpenVPN - Dropping packets when torrenting

So like many people, I set up PIA using OpenVPN and so far everything has been working fine. Currently, I have everything using the WAN gateway and anything in an alias being sent over the PIA gateway.

I decided to setup a transmission docker container (on FreeNAS) and added it to the alias. I tested a torrent (ubuntu iso) and noticed that I started dropped packets (pinging 8.8.8.8) on my desktop (which isn't going over the VPN). I tried with a few other torrents and they all behaved the same.

I checked top and saw that snort + OpenVPN both spiked in CPU but only to about 60% combined (on a two core machine).

I then used wget and downloaded a file full of random from my VPS and no dropped packets despite me getting 3.5 MB/s down on avg compared to the 2MB/s when torrenting.

I've checked the OpenVPN logs and found that it was spamming (only when torrenting is running):

Authenticate/Decrypt packet error: bad packet ID (may be a replay): [ #22652 ] -- see the man page entry for --no-replay and --replay-window for more info or silence this warning with --mute-replay-warnings

I've had a google about and haven't been able to find anything related to my circumstances. I'm going to try a different torrent client on my desktop now but other than that I'm out of ideas.

Any thoughts?