I suspect that the flouresent bulbs are getting too hot. Most recessed lighting fixtures I've seen use SPOT lighting bulbs, not FLOOD lighting bulbs. The "spot" bulbs use a higher "reflecture" and thus the heat of the spot bulb is focused OUTSIDE the fixture. And also designed to withstand the heat build up in the fixture. You may be able to use FLOOD lighting bulbs in the fixtures as well. But the lamps used in recessed fixtures are "designed to withstand" the additional heat buildup. Floresent bulbs can't take the heat.