I figured out the issue! I recently received a new external drive into which I setup XCode to write its Derived Data and Archives. This external drive was formatted as ExFAT. I have now reformatted the drive as Mac OS Extended (APFS was not an available option in my Disk Utility) and rebuilt the application. The updated pkg using the rebuilt and notarized application now correctly installs to /Applications. It's unfortunate that I could not find a Console log or display verbose enough information via "sudo installer -verboseR" detailing why the application was not being written to /Applications. Hopefully this post helps someone in a similar situation. Thank you for your time and responses.

Still no luck, unfortunately. OSX version is 15.7.2. I created a new user account, and as such, needed to add the Developer ID Application and Developer ID Installer certificates for our organization to XCode. After building the application, I had it notarized using XCode's Organizer window via the Direct Distribution option. Unfortunately, the package installer still wrote a zero-byte application to the /Application folder. I verified the installer had the correct Payload by extracting and decompressing the package data. Quite the head scratcher. Thank you for any insight.

Thank you for your reply. Unfortunately, creating a package using productbuild results in the same zero-byte file written to /Applications. I used the command: productbuild --sign <Identity> --component <PathToApp> /Applications <PathToPackage> Interestingly, if my coworker creates the application on his machine, I can then use his application in my pkgbuild script and the installation succeeds. Both his application and the application I build on my machine are signed with the same company Developer ID Application and are notarized. Both applications also run on my machine and have the same functionality, as their source was pulled from the same branch. We are both using XCode 16.2. This problem only started to happen on my machine last week. Does the pkgbuild command have a cache that can be deleted? Thank you for your time.