I was able to reproduce this issue that you are seeing. However, I do have one question. Are making sure to remove the widget from the viewport (via the “Remove from Parent” node) before resetting the level? If not, this will cause your widget to be added to the screen each time the level is reset (if you are adding it to the screen via the “Event begin play” node) and the old widget will remain on screen. This effectively means that the widget would be stacking on top of each other. I hope this information helps.
I am happy to hear that your issue has been resolved. As what else may need to be done when resetting the level, that should be it as far as UMG is concerned. However, if you have any further issues resetting please feel free to make another post and place a link here as a reply and I will be more than happy to help.