I have tested this problem with the F15 and A320, whih are the two aircraft installed but I think it's common to all aircraft that have spoilers.
I can deploy the spoilers with th "k" key but the "j" key has no effect.
I checked the keybord.xml and the "j" key 106 is indeed configured to retract the spoilers.
The internal property /controls/flight/speedbrake changes with the "k" key but not with the "j" key.
If I read the key value with the property /devices/status/keyboard/event, hitting the j" key displays 106 so the key is being read ok.
I couldn't find any key reassignments in the -set files.
Thanks