Why does my iPad Pro keep swapping from internal speaker to my AirPlay/Blutooth external speakers?

When I’m watching a YouTube video and I skip forward in the video my iPad uses this interruption in play to swap over to my bedroom Bluetooth/AirPlay speaker system. I don’t have it set to do this and I have to quickly swap it back to my iPad speaker. It’s been going on for years.

Ive searched for settings and there is nothing I’ve found to stop this “Automatic theft” of my audio output.