To expand the knowledge on this weirdness:

irb(main):001:0> module A
irb(main):002:1> module H
irb(main):003:2> end
irb(main):004:1> end
=> nil
irb(main):005:0> module B
irb(main):006:1> include A
irb(main):007:1> end
=> B
irb(main):008:0> module B
irb(main):009:1> module H
irb(main):010:2> end
irb(main):011:1> end
=> nil
irb(main):012:0> A::H.object_id == B::H.object_id
=> false
irb(main):014:0> B::H
=> B::H # it exists