URLs are no longer being rewritten in the HTML output.
This applies if you are using Resource Resolver mappings or /etc/map mappings and they are working on incoming URL resolution but not on outgoing html rewriting.
Here are some things to check that might fix the issue:
1. Go to http://aem-host:port/system/console/configMgr
2. Search for the Link Checker Service OSGi configuration.
3. Make sure that Link Check Override Patterns is NOT set to "^.". The value should be "^system/" (as that is what was in most AEM versions, AEM6.0 - 6.4).
4. Make sure that there aren't any Special Link Patterns set that could cause rewriting to not occur as well.
5. If that wasn't the issue, then search for the Link Checker Transformer OSGi configuration.
6. Make sure that Disable Rewriting is unchecked.