Yes. 120 miles would be very little to be experiencing fatigue related breakages due to tension. It sounds like that in at least one of the OP's instances it was a nipple backing off. Which could also be attributed to either uneven tension or too little tension. Hence the number of people enquiring about which side of the wheel these issues are occuring on. Too little tension on the DS will lead to so little tension on the NDS the nipples can back off. Uneven low tension can make the matter even worse. Uneven tension can also see one spoke carrying considerably more load than if it were evenly distributed across all spokes through proper tension balancing.

It would reasonably rare, but not unheard of, for the wheel to be manifestly defective.

More times than not, it's a matter of realative high and even tension. I had a 32 spoke Mavic CXP rim that was breaking spokes within 2 rides of a shop servicing it. Repeatedly! They were trying to convice me that it was beyond repair or service and that I (at 115kg) should buy some new Zipp 101's I detensioned the entire thing, brought it back up to tension and true. Tension balanced it, which because is was used and somewhat worn meant it wasn't perfectly true, no more broken spokes.