Wildcard DDNS not working with new firmware

Hi guys. I just updated from 18.06 to 19.07 and I'm having issues I haven't had previously. I have a wildcard DDNS entry that definitely used to work, but I'm now getting this error in the logs: "sanitize on domain found characters outside allowed subset".

I have a basic DDNS entry that does work (plain old domain.tld), the only difference between that and the wildcard entry is the domain field, which is formatted as *@domain.tld. I'm assuming there's an illegal character in there. I've also tried *.domain.tld, same error.

And again, this configuration worked under the old firmware, not sure what's going wrong.

I'm using cloudflare, if that's relevant, the ddns-scripts_cloudflare.com-v4 script.