After trying a few things, from using latest Xcode to switching dependency manager that imports Firebase from Carthage to Swift Package Manager, nothing seems to make a difference. At this point, I think the issue is one of the following: There's unknown issue with our project setup that removes the binary itself along with the codesign folder. Including a static framework within a dynamic framework while the former needs to be signed simply isn't supported by Apple. I then pivoted and started removing our Firebase integration and implementation in the library, and moved it to the app project itself. No issues were observed when uploading through Transporter. The build was processed, then I submitted it for review to distribute to external group on TestFlight. I will report back after it's reviewed.