New master cylinder, brake pedal on floor next morning??

Only 1 pizzy little sheet metal finger for a keeper ( various shapes with reman'd ). Two screw holes in the casting though. Might be incase one strips out, or screw rusts into the casing, breaks off?
I've never seen 2 fingers installed.
My guess, their keeper wasn't stronger than the spring.
On a positive note... this might be repairable and usable still. Pull the master cylinder. Reinstall the piston with a good keeper... or 2. More brake fluid.
And one more note.. If when you put the bolt back through the rod at pedal... Don't pull upward/outward against the keeper when tightening that bolt/nut.
At minimum that can damage the brake lamp switch or alter its adjustment. At worst? well...