Hi all, I've encountered the same on Sunday. I eventually got it open, and then found that the mechanism feels dry. The little thingy that protrudes out to catch the door also doesn't come out all the way, a little impotent! I think that it needs some lubricant, so I've applied some silicon oil and tried to work that into the mechanism, but it didn't seem to penetrate as I couldn't regain full function of it.
Do I need to dismantle the mechanism of the little impotent one and lubricate it thoroughly?
It does seem that many have struggled with the little impotent being dry, hopefully someone has figured out a fix already.