User blog comment:BertH/Technical Update: March 2, 2016/@comment-5275700-20160303014235/@comment-452-20160303150742

On w:c:kancolle, and all wikis I've tested, hovering over the notification icon now no longer opens the menu before the page is loaded.

While this is certainly one way to avoid the problem, it would be more user-friendly to just handle the menu being open and populate it instead of failing.

As it is, if you hover over the element before the page is fully loaded, you need to move the cursor off and then back on again before the menu will open.

For people who allow ads and tracking scripts, I imagine the problem is even worst while waiting for those to load.