i2s_esp32_trigger_check() in drivers/i2s/i2s_esp32.c validates the requested direction only for I2S_DIR_BOTH. The I2S_DIR_RX and I2S_DIR_TX branches read dev_cfg->rx.data->configured / dev_cfg->tx.data->configured without first checking the stream pointers. The device instantiation macro I2S_ESP32_STREAM_INIT() sets both .conf and .data to NULL for a direction the devicetree does not describe, so on an instance that wires only one direction — the normal shape for audio output or a worldsemi,ws28