I am also seeing the same issue. TestFlight installs are failing as of a build this morning upon the progress circle hitting 3/4. Previous builds install OK. This is happening for both local archives, as well as Xcode cloud archives. Checking console.app reveals: 0x16b707000 -[MIExecutableBundle hasOnlyAllowedWatchKitAppInfoPlistKeysForWatchKitVersion:error:]: 2613: WatchKit 2.0 app has disallowed Info.plist key: ISIconPlatform

Confirming this also worked in my case.