Exactly which page-level events are fired in which order to Javascript isn't always clear. If a bfcache (backward-forward cache) is active, it may interact with page changes in nonobvious ways, and may present additional unexpected events. Also you may be surprised by the firing of newer events (domcontentloaded, orientationchange, etc.).
Subtle differences in browser environment, configuration, or behavior may cause differences in exactly which events are fired. Web applications should thoroughly understand and be prepared for these differences. Careful logic may be needed to handle maintenance of state, manipulation of the back button queue, and reliance on the bfcache.