AudioReactive UDP Send causes high ping latency and slow web UI on ESP32 #5904

What happened?

Enabling AudioReactive UDP Sound Sync “Send” causes significant network latency and makes the WLED web interface slow, sometimes displaying “Connection to light failed”.

Hardware and network:
ESP32 DevKit V1 / ESP32-WROOM-32, 4 MB flash, CPU 240 MHz
INMP441 I2S microphone
54 SK6812 RGBW LEDs
Freebox Delta Wi-Fi access point
Wi-Fi signal approximately −55 dBm / 90%
“Disable WiFi sleep” enabled

Versions tested:
16.0.1, build 2606300: problem occurs
0.15.4: slightly better, but problem persists
17.0.0-dev “Kagayaki”, build 2607170: slightly better, but problem persists

To Reproduce Bug

Enable AudioReactive with the local I2S microphone.
Set audio sync to Off: web UI and ping are stable.
Set audio sync to Send, port 11988.
Close the web interface and continuously ping the ESP32: latency becomes irregular.
Earlier testing showed ping times exceeding 1,000 ms and occasional timeouts. The exact latency statistics have not yet been collected for each version.

Expected Behavior

Sending audio sync packets should not cause significant ping latency or make the web UI unresponsive.
Is there a known issue with AudioReactive UDP transmission, or any recommended diagnostic logging to distinguish a firmware issue from a Wi-Fi multicast interaction?

Install Method

Binary from WLED.me

What version of WLED?

16.0.1, build 2606300 & 17.0.0-dev

Which microcontroller/board are you seeing the problem on?

ESP32

Relevant log/trace output

Anything else?

Uptime does not reset: no reboot observed.
AudioReactive works normally with sync Off.

Disabling the Node-RED receiving flow does not resolve the issue.
The problem occurs even with the WLED web interface closed.
With Send active, the latest Info shows “send mode (unconnected)”, 112.3 kB free heap and an average LED frame rate of 43 FPS.
Node-RED normally receives the multicast audio packets to control another RGB light through Home Assistant.
No alternative access point has been tested, so an interaction with the Freebox Delta or Wi-Fi multicast handling remains possible.

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