You replied with a “solution”, but you haven’t even tested it on the response!
If I try your approach with this RESPONSE, I get that ERROR!
{"type":"MESSAGE","data":{"topic":"channel-bitsevents.XXXXX","message":"{\"user_name\":\"TestUsername12345\",\"channel_name\":\"TestChannel12345\",\"user_id\":\"TestUserID12345\",\"channel_id\":\"TestChannelID12345\",\"time\":\"2017-06-3T12:00:00.000Z\",\"chat_message\":\"cheer1 Test message.\",\"bits_used\":1,\"total_bits_used\":1,\"context\":\"cheer\"}"}}
Try doing JSON.parse on that response and see for yourself that IT throws an error.