If the steerer is bent it might be at the base, just above the crown, where the wall thickness is thinned down (the butt transition). This generally won't become any more a problem, onto it's self, then what is felt immediately after the impact. But another location of steerer damage is at the stem's bottom, especially if the stem's bottom is above the steerer's threading bottom. The steerer's threading is a weak point, what with a substantial amount of material removed when the threads were cut, as well as being what we call "stress risers", a shape/form of the material that concentrates the stresses to a single small point. It is this second possibility of bend location that can, and does, change over time as the now bent and weaker point (the threads) will tend to crack. When this happens the top and bottom of the steerer are now no longer connected and all sorts of bearing issues can happen.

Not saying that either of these is what's going on but either are possibilities. When you have another do the work (the shop) it's nice to have some understanding as to what might be going on before you have them do the work. Andy