The hide timer is 0.5 seconds for an inactive bar (if focused it will stay visible). If it takes longer than 0.5 seconds for an inactive bar to hide, that might be a bug. Do you have steps to reproduce a longer hide time?
This issue is easy to reproduce.
1. The Properties bar is docked and pinned on the left.
2. The Layer bar is docked and unpinned on the left.
3. When the mouse hovers over it, the Layer bar expands. Now, it overlaps with the Properties bar.
4. Then, I click from Layout 1 to Event sheet 1 in the top main-tabs. Its hide-timer will reset whenever I switch tags.
5. The Layer bar will then remain visible for 2-5 seconds before hiding.