We run into the same issue. We use xcrun xcresulttool merge as part of a CI script and it consistently crashes with Namespace SIGNAL, Code 5, Trace/BPT trap: 5 Terminating Process: exc handler [95946]. Used to work fine with the binaries that shipped with Xcode 26.0.1.

Also experiencing this problem. Seems to be still there with Xcode 26 Beta 5.

Just wanted to +1 here. Our freemium macOS-only app also seems to have problems with StoreKit 2 transactions since macOS 15.4. Since beginning of April, we got several angry user mails reporting that our app fell back to "free" mode. We didn't change anything in our IAP code. Some users reported that the app still has all features unlocked on their other Mac(s) using the same Apple Account. So the problem seems to be more Mac-bound than related to the Apple Account. Neither rebooting nor signing-in/out of the MAS seems to fix the issue.