Yes. That is correct. In some cases, this is described as intrasubtest scatter, and may suggest that the measure is a low estimate of ability, the examinee was not fully engaged or attending, or that their access to instruction has been inconsistent (which might happen for gifted youngsters because they are exploring knowledge on their own, in sequences not typical of the general population).
I have also seen gifted students exhibit scatter because they employed a more simplistic problem solving approach on easier items, and then switched to a more efficient, high-level approach only after failing a number of items. One student I recall nearly reached a ceiling on the memory for beads subtest on the old Stanford-Binet-4, because he was using a brute force rote memory approach, but suddenly succeeded at quite a number of items in a row when he changed his approach to one involving grouping and mini-patterns. (Not sure if my explanation of his approach is clear, but) the takeaways are 1) his actual working memory was much higher than that represented by the scaled score, and 2) I would not have derived as much information from this test if I had not explored the reason for his abrupt increase in performance near the end of the test. The qualitative information about his thinking and reasoning was much more interesting than the scaled score.
