There was, and more than just one. If the SEC was looking for stability, they would have noticed that already, but they don't care about stability. In all cases, the legacy platforms offering products based on Bitcoin have volatility triggers that halt trading the moment the market becomes too shaky. In other words, not a problem at all.
To add; I have seen large US stocks show more volatility than Bitcoin in the last six or so months, and more volatility is still to be expected.