Enabled an old line in my ssl_multicert.config and accidentally tested the action=tunnel feature. It caused the traffic_server process to crash. The code was assuming that a handShakeBuffer must be present if we are deciding to do a blind tunnel, but that is only the case if the decision is made in the SNI callback. I'm going to attach a patch that fixes the problem.
Example line that will trigger the issue. Packets addressed to 188.8.131.52 will try to convert to blind tunnel before any SSL handshake processing is attempted.