If you enable a catch-all filter, enabling "throttle" as the only action (any parameters will do), the rules themselves will match every edit, but no AbuseLog entry will be created until the throttle count is reached. While this makes sense, it is inconsistent with the status bar on top of Special:AbuseeFilter/your-filter-id, which will read:

Of the last XXX actions, this filter has matched XXX (100%).

even if the AbuseLog might be empty (e.g. if you set a high throttle counter).

Not sure if it's really possible to fix this: this kind of matches should still be recorded for profiling, but at the same time we don't want them to appear in the AbuseLog. So perhaps noting this in the documentation, or in the status message itself, would suffice.