Title: [A2DP] Regression in Bluetooth Stream Initialization – RC 20251119_1643_RC07

[dug44]

Problem: 2-5 second audio stutter/buffer underrun at the start of every track when using an external Bluetooth default speaker.

Environment & Baseline:

• Working Build: 3.77.510748 (Stable) — No stutter observed on identical hardware.

• Broken Build: 20251119_1643_RC07 (Public Preview) — Stutter occurs consistently at track transitions.

• Hardware: Nest Mini (2nd Gen) connected to external BT receiver (Yamaha R-S202 / UGREEN BT 6.0).

Technical Analysis: This appears to be a regression in the A2DP carrier keep-alive logic. The RC firmware seems to be dropping the Bluetooth sync during the silence between tracks, causing the receiver to re-handshake when the next track begins. The 200ms group delay correction does not mitigate the issue.

Ask: Investigate A2DP packet priority and buffer initialization timing in the RC branch compared to the 3.77 production branch.

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[moralesvicente]

Hello @dug44, 

Thanks for posting here in the community forum. I understand that you’re experiencing audio stuttering and buffer under-runs at the start of every track when using an external Bluetooth speaker as your default connected to a Nest Mini (2nd gen). I appreciate the detailed information you've provided; it’s a pleasure to assist you.

To troubleshoot this effectively, please answer the following questions:

• When did this issue start?
• Do you have other speakers or displays experiencing the same problem?
• What troubleshooting steps have you performed so far? (Please describe them in detail if possible).

I look forward to your reply.

Cheers,

Daniel