Hello Kevinwal,
It looks like you are no longer seeing the names of the people sending you those messages.
Let's try starting up the system in what is called safe mode. This will help us isolate this issue.
To start in safe mode, begin with the computer powered off. Press the power button to turn it on then press and hold the Shift key. Keep holding the shift key until you get to the log in screen. More information is available here: How to use safe mode on your Mac - Apple Support
The computer will take longer to start in safe mode, and the screen may have some distorted video as it starts up. This is normal. Once you are logged in, use the system and test to see if the same problem with Messages occurs.
If everything seems to work as expected, go ahead and restart the computer normally and test again. Starting in safe mode forces the computer to run some disk checks similar to First Aid. This can resolve some issues.
Cheers!