Hi,
No not a 'traditional' crash; once I connect to the BLE, I tap my app button to initiate a forward/slow motor speed. Simultaneously I get a short motor burst, the DFPlayer red LED illuminates briefly, I hear the start of the MP3 play then everything stops - the Nano33BLE green led is still lit but the builtin LED (for showing BLE connection status) extinguishes. I loose BLE connection and I have to power off/on the board to reset it and then I can reconnect and start again.