EPCS128N issue unexpected erased
We have manufactured more than 70 units of a board that uses a CIV and a EPCS128M memory during the last 5 years. The boards are working without any problem. In the last fabrication of 25 units, some months ago, we have use a EPCS with the reference "EPCS128N 991W1 V5 MYS 013". We have found a problem in a significant number of these boards. After some weeks working, when we turn on the board we detect the FPGA is not configured, and memory is erased (when we read the memory all the positions has a value "FFh"). To get more information about the problem, We use a SW that turn ON / OFF the board each 30 sec and tests if the FPGA is configured. With previous fabrications we don't have any problem, but with the last fabrication we have detected this problem in a significant number of units. After we change the EPCS memory with another reference the boards have been working properly for weeks (with the turn ON/OFF Test). Have anybody used this EPCS reference or have found this kind of problem?