If you are talking about the single bolt on the electrical adaptor, it is a captured bolt. Did it loosen at first or spin right from the start. If it was free spinning right from the start, try to disconnect it. Maybe it was never tightened.
I bought one that I could not get the bolt to start. After 15 minutes of trying, I went and got my old man glasses and could see the threads were not cut right. The adaptor does snap into place and threads very easily.
It is a cheap part. Maybe bad threads are common. Maybe someone tried to put in new and couldn't start the bolt and said good enough it snapped into place.