Quickly perform 2 actions:
1) Enter directory (double-click or Enter key)
2) go back (Alt+Left shortcut or mouse gesture)
Do these actions really quickly (as if you enterd wrong directory, in ~1 second or so)
Sometimes this will cause one extra event of entering the same folder to come with short lag [~1-2 seconds]. Essentialy this leads to dolphin staying in subdirectory, even though you hit "go back" action to go up to parent directory.
This bug does not exist in Konqueror, so i think this is Dolphin bug.

Reproducible: Sometimes