xhtml fails validation when being copied in LARA

console session

irb(main):049:0> xhtml.duplicate
=> #<Embeddable::Xhtml id: nil, name: "", content: "<p><p>Volatile organic compounds (VOCs) include man...", created_at: nil, updated_at: nil>
irb(main):050:0> dup = _
=> #<Embeddable::Xhtml id: nil, name: "", content: "<p><p>Volatile organic compounds (VOCs) include man...", created_at: nil, updated_at: nil>
irb(main):051:0> dup.save
   (1.0ms)  BEGIN
   (0.8ms)  ROLLBACK
=> false
irb(main):052:0> dup.errors
=> #<ActiveModel::Errors:0x000000059c3380 @base=#<Embeddable::Xhtml id: nil, name: "", content: "<p><p>Volatile organic compounds (VOCs) include man...", created_at: nil, updated_at: nil>, @messages={:content=>["Unexpected end tag : p"]}>