Venu 4 (fw 18.32) — RTL Trap / full watch reset when ending an ActivityRecording session (Session.stop() + Session.save())

Summary

On Venu 4 - 45mm, firmware 18.32, a Connect IQ watch-app that records an ActivityRecording session reliably causes a native RTL Trap that reboots the entire watch when the session is ended (stop() followed by save()). End users also report the app being closed and a native activity (e.g. "Running") being launched instead.

The crash is deterministic: three captured native error records are byte-for-byte identical in backtrace, program counter and register state, even though the device uptime at crash varied from ~17 minutes to ~18 hours. Free memory is high, so this is not a Connect IQ out-of-memory condition.

This mirrors an already-acknowledged class of Venu RTL Traps where a public CIQ API call causes a native trap / watch restart (e.g. CIQQA-4568, Venu 3S 17.05).

Steps to reproduce

1. Launch the app; it starts an ActivityRecording session (SPORT_TRAINING).
2. Let it run (time to crash varies — see uptimes below; not time-dependent).
3. End the workout, which runs Session.stop() then Session.save().
4. The watch either reboots (RTL Trap) or closes the app and launches a native activity.

Expected behaviour

Session.stop() / Session.save() are public documented APIs that return a Boolean on success/failure. They must not cause a native trap or reboot the watch.

Control test in progress

We built a variant that calls Session.discard() instead of Session.save() (so the activity-save page 2501 is never pushed). We will report whether the resets stop — if so it confirms the fault is in the save() UI flow.