Suppose that there is a thin rod $AB$ lying in a gravity-free environment. There are equal and parallel forces which act on it’s ends A and B.
Now w.r.t the COM the net torque is zero. That means that no matter if we look at the rod from the COM or from some random point in space, the rod will not rotate about COM. Now if we look at the rod from A’s or B’s perspective, we see that the torque about A or B is also zero. So that would mean that the body cannot rotate about A or B from their perspectives respectively.
However if we try to calculate the net torque about A from some point in space and not from A’s perspective, we get a net torque about A. But again, the body does not rotate about A.
Why are we getting this torque about A even if the body is not rotating around it?