App Test Builds can currently only be generated from the primary website and require the latest BuddyBoss plugin versions to be installed there.
This means customers must update their live production website before they can generate a Test Build and fully test the App with the secondary website plugin versions. Although the Production App itself is not rebuilt, its users already communicate with the updated primary website and can therefore be affected by server-side errors or incompatibilities. We have experienced this in a real customer project (e.g. in-app-pages gutenberg block design issues).
Please allow App Test Builds to use the configured Secondary website and its installed plugin versions while the primary website remains on stable versions.
This would provide a proper staging workflow: update Secondary, generate and test the App Test Build, and only then update the primary website.