Hi Howard,
Yes, I did think about that, and it is certainly a possibility. However, having disassembled and assembled Lugers many, many times I doubt that is the problem.
Having said that, I am sure that if the rolled part of the leaf spring were not properly engaged with the end of the sear bar it could work its way out.
I guess my main reason for this post was to learn if such a malfunction could be dangerous. On the surface I don't see any risk in this event, should it occur again; but I am no expert.
Luke