The JBL SDP-55 has not been submitted for Roon Ready certification, so we cannot provide support for the device at this point in time.
Based on the Signal Path reporting, it appears that the JBL is breaking when fed a valid MQA stream via the Roon Ready/RAAT protocol. When the device is set to “Decoder and Renderer” Roon simply passes through the bit-perfect MQA stream from the source (in this case Tidal) to the endpoint device. When the device is configured to “No MQA support”, Roon performs the MQA Core Decode (1st unfold) and then removes any MQA headers from the audio, making it appear as a normal PCM stream to the endpoint.
We will reach out to JBL independently to clarify the status of their Roon Ready integration on this device. I suggest that you follow up with their support team with this information so that they can assist you further.