First time...racquet collapsed...what happened?

[tacoben]

I'm still fairly new to stringing racquets and ran into a problem last night. I use a Klippermate. I've strung about 10 racquets so far without any problems.

Long story short, I started the mains on three racquets two days before and planned on finishing the crosses the following day. This is because my eyesight doesn't do well at night (natural day light outdoors is best for me) even with fair amount of indoor lighting. The racquets were a babolat, a technifbre, and the third was some obscure Sampras Autograph Wilson brand that I got from the goodwill store. The first two did o.k. with just the mains strung overnight and I eventually finished the crosses to complete the stringing the day after. However, when I came home last night to finish the Sampras Autograph, I noticed that the racquet collapsed near the perimeter weighing systems (PWS). So, what gives?

I asked my family if anyone accidentally stepped on the racquet...no one did, so I am curios as to why the racquet failed. Is it a bad idea to do just the mains first and do the crosses later...should I have completed the racquet all at one time? Thanks in advance for your input.