The default group configuration still works the same between 6.3 and 6.5.  I would suggest to enable debug logging for com.adobe.granite.auth.saml and see if there is some error when it tries to add the user as a member of the default group.  Also, make sure you don't have any duplicate invalid SAML...

This issues sounds similar to a known issue with crx2oak on AEM6.3. Please try running the same command using the latest oak-upgrade 1.6.20 jar here instead of crx2oak jar:https://repo1.maven.org/maven2/org/apache/jackrabbit/oak-upgrade/1.6.20/ To migrate to S3 from file datastore, the easiest way i...

Somebody might have accidentally deleted the configuration for the service user by clicking delete in the /system/console/configMgr.  I would suggest you add the missing mappings manually again via /system/console/configMgr UI in the affected environment. If the problem is affecting many environment...

SAML by design delegates the authentication itself to the IDP.  The login page you would want to customize would be on the IDP, not AEM. Do you just want the login page to have a link for the user to click that takes them to the SAML authentication process?

If the Jetty Session Timeout isn’t helping then it might be something resetting the JSESSIONID cookie so a new session is generated per request.  You might debug if the value is changing per request.  Also, investigate your code to see if you even need JSP sessions. If you don’t, then disable it in ...

Try to download the jcr:data property directly and see if the binary is corrupted or if the workflow just needs to be run again. For example:http://aemhost/content/dam/image.png/jcr:content/renditions/original/jcr:content/jcr:data 

I meant to check the actual log, not the http response, to see if the binary is missing in case you have this issue:https://helpx.adobe.com/experience-manager/kb/oak-blobstore-inconsistency-blobId.html Please send more specifics like a screenshot of the Assets UI for the corrupt images versus good o...

For the corrupted images, when you try to access them do you see an error in the error.log? If so, then what is the error?

Ah ok yeah, there is something conflicting then. If you have any custom dam:Asset or dam:AssetContent workflow launchers then temporarily disable those to see. Also compare your workflow launcher configs to a fresh install of 6.4.7.

That error isn't a known issue with 6.4.7, so there must be something conflicting with the workflow. Is the error being logged every time the dam-xmp-writeback workflow runs? Please send a screenshot of the Workflow Launcher UI. To debug merge conflict errors go to http://aemhost/system/console/slin...