this is a packet reassembly issue as highlighted by sarvanan. You could be hitting teh following defect:CSCuo35247.

Hi, Flex + Bridge feature is now available on 8.0.100.0 code. the code has already been made public on 17 Aug.here is the link: (you need to use your CCO id to get access to the image)http://software.cisco.com/download/release.html?mdfid=282600534&fl...