mTLS Fetch not working on Workers

mTLS fetch doesn’t seem to be working as described in the docs: https://developers.cloudflare.com/workers/runtime-apis/mtls. I have successfully registered the mTLS certificate and can access the variable from my Javascript Worker. I can call fetch, as shown in the docs, however my Cloudflare WAF firewall rule blocks the connection. It appears the Fetcher object is being created, along with the fetch method, but the certificate isn’t being presented.

I have tried the troubleshooting options described here: https://developers.cloudflare.com/ssl/client-certificates/troubleshooting/ and I can successfully access the website using cURL and the certificate and key. I also have a different mTLS certificate set up on my Android phone and can successfully access the website, so that rules out the other two troubleshooting options. Any help would be greatly appreciated!

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