Could you once check by sending the DFU_Reboot Text command over a PC Serial Terminal Program and compare the logs for both working and non working Modules?
The Command is /RDFU M=1. Here is the user guide - http://www.cypress.com/file/384521/download
We do not have external Host Setup ready for sending the commands for now. If you see the issue with above testing, perhaps the issue is with that particular Module.