It is not configurable through UI on FTD. However, starting with 6.2 version of FTD you can use FlexConfig to push the BFD configuration on the FTD sensor. See more on: http://www.cisco.com/c/en/us/td/docs/security/firepower/620/configuration/guide/f...

Could you provide with some screenshots of the events from the Table view of events for the ones you consider they should have been blocked?

Are object which can be used in ACP rules or wherever it requires to add an interface.