Bamboo 8.0.3 - Bamboo Artifactory Plugin 3.2.3 Maven Build Issue

[Sven-O]

I have several compatibility issues for the combination of Bamboo version and Artifactory plug-in version. I test-upgraded our dev Bamboo system to version 8.0.3 and the Artifactory add-on to version 3.2.3. Now builds are complaining about something that appears like a missing or incorrect maven library.
On several builds that uses the Maven3 add-on I am getting:
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
I do see the following jar file, /opt/maven/boot/plexus-classworlds-2.5.2.jar

This prevents me from performing the upgrade of Bamboo and the add on as well as Artifactory on our prod system.

Background:
My Prod and QA systems for Bamboo are running earlier versions of these tools.
On Bamboo prod and QA, I have version 7.2.3 which I am intending to upgrade to version 8 when I know that the Artifactory add-on will work on my dev configuration.
So on that prod Bamboo I now have the Artifactory add-on version 3.2.0 (later versions give other issues). That configuration with add-on 3.2.0 works, but it requires a workaround in all build tasks using the Artifactory add-on. I have to do a process that changes the authentication setting to "over-ride" for resolution and deployments, then run a build that will fail, then set back to none over-ride. That is not a good resolution but works for now. That error I workaround is "deployerSharedCredentialsUser=null".
The reason that I am not using a later version of the Artifactory add-on is that a higher version gives yet another error.
Plugin org.apache.maven.plugins:maven-compiler-plugin:3.5.1 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-compiler-plugin:jar:3.5.1: Could not transfer artifact org.apache.maven.plugins:maven-compiler-plugin:pom:3.5.1 from/to central (http://repo1.maven.org/maven2): Failed to transfer file: http://repo1.maven.org/maven2/org/apache/maven/plugins/maven-compiler-plugin/3.5.1/maven-compiler-plugin-3.5.1.pom. Return code is: 501 , ReasonPhrase:HTTPS Required. -> [Help 1