This one is a tricksy one, but it shouldn't be too hard to fix.
When you click on the portrait of a non-active crewmember to switch control, Unity is giving input focus to that character portrait. Thus, whenever you press space or enter, Unity acts as though you left-clicked it again.
STR:
- Have more than one crewmember in your crew (including yourself)
- Switch the lower panel to "Crew" view
- Click on the portrait of your non-active character to switch to them
- Press spacebar or enter, and watch their inventory pop up
- Press capslock to switch characters and then spacebar or enter, and control will switch back to them
This does not happen when you click the character portrait of your active character, so my strong suspicion without diving into the code is that the "character portrait click" handler has logic something like
center view on crewmember
if not active crewmember:
switch to this crewmember
return
toggle inventory display
switch input focus away from this button
and you can just move the "switch input focus" part to the top. Alternately, since this game is mouse-only, you could just unbind space and enter from the uGUI input bindings, but that might cause more problems than it fixes.