For the first a temporary fix which disables the auto-scroll feature was applied, in order to prevent seg.faults: https://git.xfce.org/xfce/thunar/commit/?id=00ed70512ae514e94475796cd583d04c6b76c192 A proper fix is in work.
Alexander Schwinn referenced this bugreport in commit a63b1732d5846652151649073ebe15ac8b0ab2cb Segfault when pressing "folder up" on pathbar (Bug #13987) https://git.xfce.org/xfce/thunar/commit?id=a63b1732d5846652151649073ebe15ac8b0ab2cb
fixed on master, to be released
resolved: fixed