My new 5s (16GB) is having the same issues. Here are some details oh age noted:
- Pages and Numbers are both at fault on my phone.
- The issue can be reproduced IMMEDIATELY after rebooting by double clicking the home button or clicking it once
- The issue was not resolved in the update of the iWork suite
- The issue involves previous iCloud documents as well as new ones (created after most recent update)
- Blue screen also randomly occurs after returning to the home screen from Launch Center. I haven't figured out what trips the switch in this situation though.
- This is a 5s-only issue suggesting a hardware problem and not software.
I too use the iWork suite for business and have no alternative to my iphone aside from my computer. Any update from apple would be appreciated but I'm sure the issue is being looked into as we speak.