I understand. Thanks again.
This was fixed in version 16.2 of Advanced Installer released on August 1st, 2019.Indeed, I was able to reproduce this behavior. It seems like this is an issue of Advanced Installer in what regards the support for Init Events for the Pre-Install prerequisites dialog.
A fix will be available in a future version of Advanced Installer, thank you for bringing this to our attention.
We will update this thread as soon as a fix will be available.