I’ve noticed that in latest develop branch, AudioPluginHost fails loading plugins (tested with Apple’s AUBandPass on macOS 11.4) and bisected it to Accessibility: Fixed some focus issues with modal components · juce-framework/JUCE@7aff57c · GitHub
Possibly it’s also broken on other platforms and formats, will update when I discover more information.
Edit: It appears that the very latest commit 928cc5f80c43d7fd0e0b7bbec654d5b3b3d7b614 fixed the issue, nm