The second instance of the installer opens during installation (Wix 4)

[smmicrolab]

Hello everyone, I don't even know how to describe it. During installation (and more specifically, after unpacking the files and launching the deferred Custom Action), a new installer window opens. Previously, this behavior was only on wix 3 x86 systems, and now on x64 systems. Maybe someone has encountered or knows what the problem is?
I do not know what data can/ should be attached, but I will try to throw it off if desired.