First of all, my kit is a Blue 21 RT and I have a Sena SRL with a RC3 remote on the handlebar and the bike has its own Samsung Galaxy S10. I also have a S10 as a personal phone. The bike phone also has a SIM courtesy of my Company (I am the MD of the Company so that is why it has a SIM).
I have zero connectivity issues with the phone and the TFT and more or less everything is settled on that front.
This makes sense. Thing is, I see the streaming music issue when I'm connected to bike only, no phone to Sena. Music stops between songs. I can hear the next song start, but the bike stops the music for some reason. Not sure why.I have tried this in the past and it just caused conflicts between the devices and made the connection unstable. I now keep it simple - phone connected to TFT only and Sena connected to TFT as primary only. Downside is that you loose some of the features of the Sena (Siri, voice dial, using the Sena app for headset settings etc).
Your music issue could be as a result of such conflicts - your music is currently being pushed to both the TFT/Sena and also direct to the Sena - so the Sena will choose which music source to play (usually the primary channel) but if it does detect music on the secondary channel, it will want to swap to this and vice versa.
This is an extract from the SRL2 manual :
If you have two audio (A2DP) devices connected to your headset then the audio from one device will interrupt the audio from the other device. For example, if you are playing music from the primary mobile phone, then it can be interrupted by playing music from the secondary mobile phone and vice versa.