Hey everyone, I know I'm late to this party, but I created an account just to add a possible solution.
Several versions ago, the concept of "Chat" was introduced to SMS/Text in Android.
I recently upgraded my phone (Pixel 5), and every text message received from someone with a newer phone resulted in the encoding being read on my 2015 Sierra. I did some testing and figured out it was always someone with a newer phone that also supported this Chat feature.
To eliminate this, I went into the Android Messaging app and clicked the "..."button in the top right.
Then Settings
Then Chat Features
Disable Chat Features (turn slider off)
This turns off things like read/delivery receipts as well as the indicator that the other party is typing and reverts your phone back to the basic SMS functionality as opposed to using the Chat feature.
My truck no longer reads the encoding!