No. I've even reverted it back to only Woocommerce + loyalty plugins and default template, and the issue was still there. I do have Cloudflare CDN (Rocket.net hosting), but I also asked them to disable caching for referral URL's and asked Rocket support if they have any other caching / redirects / something happening that could be interfering with the links, but they said no. It's a bit shit that I don't have direct access to the Cloudflare admin panel, but then again, Rocket seems to be quite a professional company so if there was something fundamentally flawed in their setup, I'm quite sure they would know it by now.