Windows installers freezing on GHA as of Aug 5

I am the maintainer of rtools40, the Windows toolchain bundle for the R project. The rtools40 installer consists of a pretty standard innosetup config. Over a million people use this.

As of recently, all unattended installations of rtools40 on GHA freeze indefinitely. The installer itself has not changed. Has something changed in the windows-latest image could cause the installer to present a user confirmation dialog where it did not before? Perhaps UAC related?

Some examples: https://github.com/r-devel/r-svn/actions

Moving discussion to --> https://github.com/actions/virtual-environments/issues/1369