Hello Rik.
I've asked my provider and he has found that such name is inside scripts/letsencrypt.sh
I just checked and indeed that line is in there. However I only said I've never seen it before.
So we are back to the main question: Why DA cannot create _acme-challenge but can update it? Doesn't sound a problem of nameservers, sounds more like a bug.
Maybe a bug in the script for updating then.
So in regard to you explanation this is not local.
That depends. If your hoster is using this nameserver and one of the nameserver ip's is from the server, then they are running locally.
You can also use a nslookup command for that like: nslookup ns1.nameserver.com
which should return an ip address.
Back to your issue. It must be known first if the nameserver is locally. If the dig does not work then use nslookup.
If it's not running locally then there might be a little issue in the script, but you could have another issue on the next update.
So if nameserver is not running locally then we have to talk to SMtalk about this. Because everybody including him is saying that auto update on wildcard domains is not possible when namesevers are running externally. Because DA can't create the challenge record.
So if it works if you create a test record manually, there must be something there which I can't explain but probably isn't working as designed either.
If nameservers are locally, then there is an issue anyway because DA should be able to create the record itself.
So I guess we need DA Support or SMtalk anyway to get more clarification about what's happening. But it would be good to know for sure if NS is running locally or not.
You could ask your host. Maybe you can also ask if you're the only one having this kind of issue on the server.