that is a claim by the Pentagon, which is so categorically untrustworthy on matters such as these that it really is not worth taking seriously. their actually-backed-by-data estimate on the same munitions is a 14% dud rate (and there are reasons to believe the rate is higher than that) and that quite literally follows the section you are excerpting from.

The editorial board cites the fact that the cluster munitions being sent by the US have a “very low dud rate,” and will therefore pose less of a risk to civilians. The Pentagon claims that the munitions it is sending have a dud rate of 2.35%; even if that’s accurate, it exceeds the 1% limit the Pentagon itself considers acceptable.

According to the New York Times’ John Ismay (7/7/23), a failure rate of 2.35% “would mean that for every two shells fired, about three unexploded grenades would be left scattered on the target area.” There is reason to believe that the true dud rate may be much higher—possibly exceeding 14%, by the Pentagon’s own reckoning.