Hi @Michael Mester,

This will usually happen if you are using a local repository to install the HDP and ambari cannot fetch the version information from : http://public-repo-1.hortonworks.com/HDP/amazonlinux2/3.x/updates/3.1.0.0/HDP-3.1.0.0-78.xml

and instead it fetch's from stacks defined in /var/lib/ambari-server/resources

and this HDP-3.1 is minor version of HDP-3.x the stacks defined in abouve location will be having the HDP-3.0's versions information.

you can either ignore displayed versions in stacks and versions page.

or

you can go to ambari database and edit the repo_version table using following commands

[root@asn1 ~]# psql -U ambari ambari
Password for user ambari:
psql (9.2.24)
Type "help" for help.
ambari=> select version_xml from repo_version;
                                                            version_xml
-----------------------------------------------------------------------------------------------------------------------------------
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>                                              
.....<SOME DATA>... '
ambari=> update repo_version set version_xml='<USE_SAME_DATA_ABOUVE_EDIT The versions of Services as per this url : http://public-repo-1.hortonworks.com/HDP/amazonlinux2/3.x/updates/3.1.0.0/HDP-3.1.0.0-78.xml>';

Please note: always take a Database backup before any operation to ambari and stop ambari server.

Default password of database if postgresql is bigdata

PS: Please accept this answer if you find it helpful

only perform Database operations if you have prior experience or as mentioned please ignore what ambari show's in stack and versions page.