I figured it was related to the queues not being restarted, as I've had that issue before.
I had added php artisan queue:restart into the envoyer deploy script, but I had forgot to tick the tiny apply to server checkbox at the bottom.
This actually didn't work after redeploying, but SSH'ing into the server, and running the below commands in the latest release directory, seems to have done the trick.
php artisan config:clear
php artisan route:clear
php artisan view:clear
I'm not sure which one of those commands changed things or why, so If anyone has any insight into what the issue was and how I can prevent it in the future (perhaps by adding above commands to deploy script), I'd be really grateful.
Thanks.