It will indeed transfer some heat into the i/cooler, but sometimes that's the only place, most don't need as much cooling effect as the larger RS500 item can give, so can afford to sacrifice some area, the coolest point in the i/cooler will be at the top between the in/out pipes to/from it, so placing a cooler lower down won't hurt as much, although I'd always fit behind the i/cooler personally on top of the rad, there are imo several advantages to this, the prime one being it is protected from stones and flying debris, it will puncture the i/cooler first losing boost which you will notice, if it punctured the oil cooler you may well not notice till you hear the death rattle.
tabetha