Crossbows shooting in a straight line has been a common gaming trope since at least Final Fantasy Tactics, the idea being that on the scale of the map, the power of a crossbow means that the arrow effectively flies in a straight line.
Not sure it needs a fix, but it wouldn't bother me either way. I will say it's not necessarily bad to have some differentiation between crossbows and normal bows, otherwise it's just reskinning.
5e also assumes projectiles go in a straight line, as has always been the case in D&D.
