Maybe there’s a special case for local subnets?

Here’s what shows up for me (in portuguese):

Clicking on more details, only allows me to check the certificate:

Here’s the translated details:

Safari warns you when a website has an invalid certificate. This can happen if an attacker has compromised your connection. For your protection, you cannot visit this site. You can check later to see if the problem has been solved. You can also contact the site owner to report this error.

To learn more, you can see the certificate.

Said certificate:

Edit: on the latest iOS version (27) btw.

Yes, but safari doesn’t even let me ignore the warning, it has a explanation in detail, and only allows closing the website.

Orion browser (maybe safari?) on iOS detected the revoked certificate, and asked me to confirm before accessing the website while warning about the dangers.

Joplin, I also self host my server and sync between my devices.