Sorry for the certificate mess!
OpenBSD’s acme-client has a bit of a learning curve and getting it to play nicely with prosody took a little more effort than I expected.
I’ve finally got everything working together and automated, so expired certs should no longer be an issue.
Thank you all for your patience!
Be on the lookout for another update here shortly about an upgrade to OpenBSD 7.6 which is likely to release within the coming week.