Apple Feedback told me to try with 26.6.1 (which I think was the newest version as of that time). My team and I have tried it with both that version and I think the newest iOS 26 (26.6.2), and fully updated WatchOS, and in both cases it seems to work normally now. We can install the app from the phone to the watch as we did before. So I think Apple has fixed it and the resolution is to update to the latest versions of iOS and WatchOS (at least iOS 26.6.1).

I haven't gotten any updates from Apple support regarding a fix being released. I just tested now with iOS 26.5.2 and WatchOS 26.5 (latest on both my devices) and the problem seems the same. I have not tried the 26.6 RC though.

Thank you for the response, it is good to hear that it is being worked on!

Ziqiao Chen, I do have a Feedback report filed. Here is the info: FB22807635 (Cannot Install Enterprise Team Watch App From iPhone in 26.5) Please let me know if you need any more details. Thank you

That does sound similar to what I am experiencing. I wonder if there is some issue introduced by 26.5 that prevents the watch from verifying the app signing on install, or communicating with the iPhone to do that?

An update: I heard back from Apple in Feedback Assistant. It appears that they intentionally made this change with WatchOS 9 and iOS 16. Here is the reply I got from Apple: "Please know that this was an intentional change, and the documentation is being updated to reflect this. See https://developer.apple.com/documentation/uikit/uidevice/1620015-name for the analogous change in iOS." It sounds like the default in WatchOS 9/iOS 16 is to return a generic device name unless you request an entitlement from Apple for your app to use the actual device name: https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_developer_device-information_user-assigned-device-name

We have run into the same issue on our Series 6 and Series 7 watches since the WatchOS 9 update. When running on a device with WatchOS 8, WKInterfaceDevice.current().name returns the expected device name (matching the one in Settings > General > About > Name). But when running on any WatchOS 9 version, it always returns "Apple Watch". We have also found that the correct name is returned in WatchOS 9 on the simulator, but not on physical devices. We have noticed this with an older Storyboard-UI watch app where the device name has been working for a few years without incident. We also tested it with a small SwiftUI test case with the same results. It doesn't seem to matter which version of WatchOS 9 is used, even up through WatchOS 9.1. I have a Feedback Assistant report in to Apple, however I have not gotten any response on it.