iOS Scroller @scroll 事件偶尔失效

iOS Scroller @scroll 事件偶尔失效，导致滚动逻辑失效，快崩溃了，经常偶现找不到问题原因，版本为0.28.0

Start by reproducing the intermittent @scroll failure in the iOS Scroller on version 0.28.0 and determine when the scrolling logic stops receiving events. No source file or test is identified in the issue, so trace the iOS Scroller event path first. Done means the failure cause is identified and the @scroll behavior is reliably restored.

Written by the indexing model from the issue text.