System Information
Windows 7 Ultimate - 64 Bits, NVIDIA GTX760, Intel Core 2 Quad 6600, Memory: 8 Gb

Blender Version
Broken: 2.70a Hash: f93bc76

Short description of error

Exact steps for others to reproduce the error
Add an object and set to collision object. Add a second object and apply a cloth modifier, add a force (wind force). Bake and ok. Add a third object, apply cloth modifier, bake, and the wind will not affect this new object. Sometimes wind do not affect the first object also.

A workaround that i found is change the force to, for example, a vortex, bake, free this bake, change the force to wind and rebake and the cloth will be affected. But this take much time in order to do this bake for nay new object (i have to do step by step because baking all take a long time and i have to see the result to check is ok for every object).

Sorry for my english i am not a native speaker.