Hi @bko,
Thanks for your post – it helps to explain and confirm my doubts on the issue I'm facing. I'm getting a very similar situation regarding a websocket implementation that works with Spacebrew. This implementation requires extended payloads that go beyond what TCPClient is able to handle. The root of my issue is the websocket sending continuous streams of data to the Spark Core in short intervals, which I suppose is similar to what @mleonh is facing.
Long story short, I had to resort to MANUAL mode and rely on a disconnect/reconnect routine in my Spark code to get around the buffer issue. Running my code with spark cloud connectivity results in a repeatable hard fault SOS: