Links randomly changing to ip address

Hey all.

Summary

Our hyperlinks are randomly changing from domain name to ip address.
i.e.
From

To
123.456.789.123/index.php?id=XXX

After initial install all links had IP address. We set the http_host system setting which successfully then showed all links as the domain name. Seemingly randomly the links show as the hosts ip address. This occurs for everyone at the same time so not client related.

Step to reproduce

Unknown, appears to happen randomly. It can be fine for days then suddenly occur. Running Refresh URI’s fixes the issue.

Environment

Intranet site (not exposed exernally)
MODX Revolution 2.7.0-pl (traditional)
Rocky Linux 8.6
nginx 1.14.1
MySQl 10.3.32-MariaDB

Maybe you also have to add a system setting site_url.

What is the value of the system setting link_tag_scheme?