The problem is that they did not fire a single shot at the bombarding fleet. Not one shot from four units and this has happened with previous encounters. In fact, none of the artillery in the hex (and there is quite a bit) shot at all. So, the IJN can sail in with impunity, not have their aim disrupted at all.
It can't be range because IJN CLs came within 2,000 yards and it can't be low light since at a separate hex Chinese mortar units shot at a bombarding TF on the same night. They didn't hit anything, but at least they were trying.

