Testing Rem in the hideout, we found that if he's stunned while casting ult (at least in this case he was stunned by Lightning Scroll), the light beam from his cancelled ult persists, this remains between deaths and stacks
This also happened to me in the very first game I played. It made it almost impossible to see what was going on in that direction for the whole game. The light stayed facing the same direction as the way I would spawn and was not influence by my camera or character model changing.
had the same bug show up in the lobby, im not sure if it had something to do with being stunned, I just did a second naptime after the first and it did it.