The explore missions which don't involve combat have never given me SP. Even through OB.
Also you can only do that once and generally if you enter at the beginning of the fight you have to stay until the end to get the Deep Space Encounter quest SP.
Its probably a bug that you can enter a finished one and click the "Hail" button and get SP.
every easy portion of the explore missions yield SP. You can walk around a planet and scan 5 things and get points. And you have always been able to get sucked into a defend mission and press the free XP button in the corner, bug or not, and has zero effort compared to the data missions.
And in OB it did yield SP for those missions, this is recent change and needs attention back in the other direction.