I understand this is an old topic, but hope this helps someone because I ran into the same problem.
Make sure you aren’t creating a second text widget on top of itself. A good way to check this is to print a debug string in the “Construct” Event in your HUD BP/C++ class. If you see more than 1 message printing, then your text widget is being painted on the screen more than once.
In my case, I accidentally added the same HUD in the gameMode and HUD classes.