6.34 (2016-Jan-29 10:25) problem

Dear All
i have a problem after updating to 6.34 (2016-Jan-29 10:25) on ccr1036-12G-4S
the problem is suddenly after update i noticed that i don’t have link on one of my interfaces and after troubleshooting i found that the interface has been changed to sfp3 it was ether5 and it changed to sfp

i changed it and everything went well
i just want to ask why would upgrade will change such configuration to me
also i want to ask if something happened in the future after i upgrade how i can downgrade directly ?

thank you in advance

no one interested in my post ?
any advice ?

Are you the only one that have access to this router? What does logs indicate? Do you use log save on disk, so they persist through reboot?

yes i am the only one
and i don’t have log to disk