Olympus HLD-6 shutter button problem
If the contact points are not making correct contact, that could be a problem. Even though the grip is able to lock, the contact points could be a little off in alignment. It happened to me.
Yes, try cleaning both sets of contacts (the female with an old, clean, dry toothbrush. Also push the male pins with something non-greasy to check the action. The wheel does need to be fairly tight. After some use, the male pins cause indentations in the female contacts, but normally still work fine.