Volume automatically going to 100%

So I’ve just bought a iPhone 14 pro max from previously having an iPhone 11 and when I connect to Bluetooth my phone volume goes to 100%, I understand this is so the music volume is controlled with the car rather than your phone whilst driving. But when I disconnect from the cars Bluetooth the volume goes back down to where I had it but shortly after goes back to 100%. This is really annoying as if I open something on my phone it is blaring when I never put the volume at this level. I haven’t ever had this problem with my old phone so why is it happening now?