[pteraspidomorph]

I had a problem with a similar effect some time ago but I run my own DNS (no Cloudflare). I accidentally clicked a button in my control panel to regenerate the zone keys, which means the published keys mismatched the new zone signature for a couple of days until I was able to get the registrar to update them and everything propagated (even when a registrar supports the .eu TLD they are usually severely lacking in automation). The control panel devs have since added a confirmation dialog!