I am facing a strange problem with the Firepower management center 4000 (FMC) that was formaly known as Firesight Management Center. Cisco recently release SW code 6.1 for the FMC. With SW 6.1 the 10 Gig interface have become avaialble. The 10 Gig ports have been there in hardware but you couldn´t use them with the previous software releases.
Regarding to connections to Firepower device and logging the 10 Gig interface works as expected. When it comes to manegement webgui it shows a strange behaviour. You can connect to the IP address that you have configured on the 10Gig interface. Everytime when you try to enter the interface config tab the FMC webgui it reboots. That is working without any issues on the 1Gig interface.
My workaround is to use the 1G Interface for the WebGui and the 10Gig Interface for peering with firepower devices. Sadly at the moment there is no LACP or etherchannel on the FMC at the moment available. That would help to connect the FMC with more redundancy.