The most common reason for a 50% visitor loss is the domain's DNS setup in Cloudflare.
If you check the domain, make sure you don't have two records for domain.com, e.g. an A-record and a CNAME.
Cloudflare makes it a bit easy to make this mistake, but if you have two it will 50/50 split responses between them, so half of the traffic might not even go to FunnelFlux.
Check that first as its the most common reason for this, if that's not the reason we can dive in a little further.