I found this elsewhere but there is a checkbox in Packages to "allow downgrade." Have you attempted this option? It took me a while to find this solution as well. Original source: https://forum.juce.com/t/installer-issue-with-au-component-not-being-installed-but-vst-and-aax-are/48017

I found this elsewhere but there is a checkbox in Packages to "allow downgrade." Have you attempted this option? It took me a while to find this solution as well. Original source: https://forum.juce.com/t/installer-issue-with-au-component-not-being-installed-but-vst-and-aax-are/48017