I've been having this problem for over a year now, but when I am connected to Bluetooth and I'm listening to Pandora, when I receive a text message it immediately marks the text as read and my text notification sound won't go off. It's not a specific Bluetooth, I have 4 different Bluetooth Devices I use depending on where I'm at and it's only if I'm listening to Pandora, does anybody know how I can get my text notification to go off again and stop Pandora from marking my text messages as read? Phone calls aren't an issue at all, just texts.
I have seen some reports where this issue occurs with iOS 13, 14, and iOS 15 - outside of the Pandora Community. There's a bug where Apple messages indicates that a message has been read even if you have this feature disabled. A reboot of your device could resolve this temporarily.
I would recommend contacting Apple to report this and asking for any suggestions regarding this feature. Based on your message, it sounds this only occurs when you're using Bluetooth.
I was able to locate a similar thread on the Apple Support Community here.