If I try to delete an interface which has a static subnet defined i get the following error message:

2017-05-31 11:10:46 965c8873 [app] [W] Remove DHCP Settings for bando task failed with the following error: undefined method `destroy' for nil:NilClass
 | NoMethodError: undefined method `destroy' for nil:NilClass
 | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:67:in `block in del_dhcp'
 | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:67:in `each'
 | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:67:in `all?'
 | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:67:in `del_dhcp'
 | /usr/share/foreman/app/models/concerns/orchestration.rb:216:in `execute'
 | /usr/share/foreman/app/models/concerns/orchestration.rb:144:in `block in process'
 | /usr/share/foreman/app/models/concerns/orchestration.rb:136:in `each'
 | /usr/share/foreman/app/models/concerns/orchestration.rb:136:in `process'
| /usr/share/foreman/app/models/concerns/orchestration.rb:60:in `on_destroy'

https://gist.github.com/RuriRyan/283b99487a3b54777bb6b8022c5f395d

Apparently it tries to remove DHCP Settings, but the subnet is Static, doesn't make too much sense for me.