jruby destructuring oddity

enumerator.rb

pairs = [[1,1],[2,2],[3,3]]

enumerator = Enumerator.new do |y|
  pairs.each { |x| y.yield(x) }
end

puts "Array:"
puts pairs.find {|a,b| a > 2}.inspect
puts pairs.find {|a,b| b > 2}.inspect

puts "\nEnumerator:"
puts enumerator.find {|a,b| a > 2}.inspect
puts enumerator.find {|a,b| b > 2}.inspect

output.txt

# MRI 1.9.3-p385
$ ruby enumerator.rb
Array:
[3,3]
[3,3]

Enumerator:
[3,3]
[3,3]

# Jruby 1.7.3
$ ruby enumerator.rb
Array:
[3, 3]
[3, 3]

Enumerator:
3
NoMethodError: undefined method `>' for nil:NilClass
  (root) at enumerator.rb:13
    call at org/jruby/RubyProc.java:249
   yield at org/jruby/RubyYielder.java:86
  (root) at enumerator.rb:4
    each at org/jruby/RubyArray.java:1613
  (root) at enumerator.rb:4
    call at org/jruby/RubyProc.java:249
    each at file:/Users/simon/.rubies/jruby-1.7.3/lib/jruby.jar!/jruby/kernel/jruby/generator.rb:246
    each at org/jruby/RubyEnumerator.java:206
    find at org/jruby/RubyEnumerable.java:563
  (root) at enumerator.rb:13