A batch finished but some images were not changed

This is usually correct behavior rather than a failure. By default the app skips any image already at or under your target, so a run over a mixed catalog legitimately reports fewer images changed than images scanned. An image is left alone when it is already smaller than your maximum dimension, already under your file-size ceiling, or already in the output format you asked for. If you genuinely want every image reprocessed, turn off the skip-if-smaller setting for that run, and expect the chargeable count to rise accordingly.