Hello Fujii-san,
Stop counting skipped transactions under -T as soon as the timer is exceeded. Because otherwise it can take a very long time to count all of them especially when quite a lot of them happen with unrealistically high rate setting in -R, which would prevent pgbench from ending immediately. Because of this behavior, note that there is no guarantee that all skipped transactions are counted under -T though there is under -t. This is OK in practice because it's very unlikely to happen with realistic setting.
Ok, I find this text quite clear.
One question is; which version do we want to back-patch to?
If we consider it a "very minor bug fix" which is triggered by somehow unrealistic options, so I'd say 14 & dev, or possibly only dev.
-- Fabien.