There's clearly a 'dead-end' effect, yes - you can see it clearly in the first graph, with the thick black bar each chapter receives, proportional to its time as the 'latest' chapter. EDIT: you can also see this effect vividly in the Unexpected Circumstances per-chapter graphs.

But I don't see why this would distort an entire region compared to another region: every reader in the 40-70 region is going to dead-end in the 40-70 region, almost by definition, unless they start reading at the very tail end such that an update happens before they finish that region (and would leave a dead-end review, one chapter before).