SwiftUI template in Instruments 26.4.1 shows empty channels on iOS 26.4.2 device — even with a minimal TimelineView repro

Hi all,

I've hit a reproducible issue where the presence of the SwiftUI instrument in a template prevents any data from being recorded, including from the other instruments in the same template. Removing the SwiftUI instrument immediately restores normal recording.

Environment

• Host: macOS 26.4.1 (25E253), Mac mini
• Xcode / Instruments 26.4.1 (17E202)
• Device: iPhone 17, iOS 26.4.2 (23E261) (physical device, USB-attached)

Symptom

Recording the same app, same device, same session, only varying the template contents:

• SwiftUI template (as-is) => All lanes empty across the entire recording

• Same template with the SwiftUI instrument removed => Data collected normally (Time Profiler samples, Hangs, etc.)

So it seems not an issue with the SwiftUI lanes specifically being empty — including the SwiftUI instrument appears to silence the entire recording.

Steps to reproduce

1. Open Instruments → pick the SwiftUI template (or build a custom template that includes the SwiftUI instrument alongside, e.g., Time Profiler).
2. Target the device, attach to the running app.
3. Record for ~10s, interact with the app.
4. Stop.
5. Result: every lane is empty.
6. Edit the template, remove the SwiftUI instrument, re-record with no other changes.
7. Result: normal data appears in the remaining instruments.

Questions

1. Is this a known regression in Instruments 26.4.1 on iOS 26.4.x?
2. Is there a workaround to use the SwiftUI instrument on this OS combo (different Xcode build, runtime flag, entitlement)?
3. Does it work for anyone on iOS 26.4.x + Xcode 26.4.1, or is everyone seeing this?

I can file a Feedback if confirmed as a bug — wanted to check here first in case I'm missing a setup step.

Thanks!