macOS 15 beta refusing to run IFW maintenance tool - "Code Signature Invalid"

We've encountered a problem with the macOS 15 beta (build 24A5331b) where the maintenance tool deployed by a Qt IFW online installer cannot be run. Upon doing so, macOS pops up a message saying the application cannot be opened, and the crash report reveals this is because the main executable gets terminated because its code signature is invalid (see attached log).

This used to work on macOS 14; we had observed with our own applications that macOS seems to accept executables deployed by signed and notarized executables as valid, "inheriting" their validation state. This seems to no longer be the case in macOS 15; I'm not sure if this is an intentional change in behaviour on Apple's part or not and will raise the issue with them also.