Um, I'm not sure if the problem was fixed or not, but I had a similar problem.
And what was happening with my Filco (happened to my backspace actually; whenever i pressed down, the key just got stuck, and i would have to use a pincer grip to just lift it up again).
So what was happening was that I had my stabiliser pins 180 degrees the wrong way. When I changed them around, it seemed to fix it perfectly. (I didn't actually realise that the stabiliser pins are NOT symmetrical lol

).
Also, you can buy some new stabiliser parts from WASDkeyboards, if you think any of the parts are damaged. They are pretty cheap, and I've had good service from them =D
Hope it's all fixed =D