Some forwarded emails not arriving

I recently set the nameserver and mx records of a domain to cloudflare, and have set up catchall email forwarding to forward to my gmail account.
Only emails to some addresses are arriving at my gmail account, these are laurence@ and loz@
Emails to other prefixes are not arriving, but they do show in the Activity log on the Cloudflare email routing page with the result column showing “forwarded”.
It’s weird because the two addresses that are working are the two that I explicitly configured for fowarding at 123-reg (my domain registrar) but as I now have my nameservers and MX set to use cloudflare, the 123-reg settings should have no effect. There’s nothing in spam. Any ideas?