(a) Going through my files and folders in the File Browser (Ctrl+B) (pic 1) and
(b) selecting a random file or folder (pic 2)
... that's buried deep at the, say, 7th level always makes the browser jump to the original horizontal state, i.e. to the 1st level, i.e to the left.
From what I remember this is limited to Linux, although it's been a while since using Picard on a Windows machine. I'm using the daily build right now, but this also occurs with the stable release from the Mint/Ubuntu repository.