On an M5Stack CoreS3 StackChan running ESP-IDF 5.5.4 and Tailscale, the face froze with eyes half-open while idle. After moving mbedTLS buffers to PSRAM and offloading HTTP polling, FreeRTOS run-time stats and backtraces traced the remaining stalls to lwIP and Tailscale tasks on Core 1 and blocking USB CDC writes.
Tested on CoreS3 + StackChan Body: head taps caused ghost recordings and phantom Qwen3-ASR replies. Fixed across 3 tiers with VAD, emotion tags, and lip sync.
Tested on CoreS3 + StackChan Body: the 3-zone head pad works as a talk button, strokes need a 30–400 ms gap between zones, and servo motion leaves touch stuck until recalibrate().
Flicker and ghosting on 74HC595-based seven-segment displays often come from latch boundary placement rather than power issues. A look at how QUAD7SHIFT's 16-bit atomic update avoids the problem.
