Our MY1992 940 showed bubbles after a while on all horizontal areas. The paint was "blistering".
The possible cause may have been that the color in the factory paint shop had been changed just
before our car was painted and that some residual water was still in the system after cleaning it from
the previous colour. During summer, the sun "activated" the inclosed droplets.
I thought this could have happened since Volvo hadn't completely ironed out all problems of using
water solubale paint at the time. After a long battle, the car was completely sanded and repainted.
If your XC suffers from the same "disease", I may show blisters in different stages of development.
On our 940, they were clearly visible as domes of several heights and craters under the microscope.
Perhaps the hood of your car was completely redone, or perhaps it was showing the first signs
of blistering. The question remains whether the chip on the hood was just that.