Inconsistent behaviour with spin boxes on linux with orca

0) make sure both orca and transmission-qt are running.
1) Open the menubar and navigate to the Edit -> Preferences.
2) In the preferences window tab around until you focus a spin box. Usually these contain a numeric value which can also be edited directly. Pressing left and right arrow keys to read current value letter by letter is working like it should however when pressing up and down arow to increment or decrement the value the first change is reported correctly and subsequent changes are not. Either the label associated with the control is reported on each value change or the focus is moved to a different control as I am testing this with transmission-qt.