You are probably experiencing cases in which papers in the list are not updated, even after several trials. There are two important cases to distinguish.
First case: just a few papers are updated and several are not. This is probably to the fact that we are sending an unsuitable query to GS. Please, report these cases and we will change. Your feedback will help us in devising more general heuristics to automatically figure out wich query must be sent to GS to improve the coverage/recall of papers to be updated.
Second case: several papers are updated and just a few papers are not. There are many possible causes, some of them being, (1) our schedule policy is leaving black spots; (2) GS simply doesn’t have information on this paper.
We are aware of (1) and we are currently working on new policies to minimize the papers not updated, while keeping the update costs small.
Anyway, an important thing to keep in mind, for now, is that our current schedule policies try to prioritize the update of papers that are likely to change the value of the h-index. That is, papers that have relatively too many or too few citations may take long to be updated.
However, having all/most papers update is important because our goal is also to provide other impact metrics, such as Impact Factor and normalized H-index, which required better estimations on the citations of ALL papers, and not only those who have citations. Thus, we are still improving our policies. Any ideas are very very welcome.