BigDecimal does not Marshal round trip in ruby 2.1/2.2 (did in 1.9.3)

big_decimal_marshal.rb

# Ruby 2.1.2

2.1.2 :173 > x = BigDecimal.new(1.0, 1)
 => #<BigDecimal:7ffcee09bb98,'0.1E1',9(27)>
2.1.2 :174 > y = Marshal.load Marshal.dump x
 => #<BigDecimal:7ffcec5d9ee0,'0.1E1',9(18)>
2.1.2 :175 > x == y
 => true
2.1.2 :176 > Marshal.dump(x) == Marshal.dump(y)
 => false
2.1.2 :177 > x.precs
 => [9, 27]
2.1.2 :178 > y.precs
 => [9, 18]
 
# ruby 1.9.3
1.9.3-p551 :044 > x = BigDecimal.new(1,1)
 => #<BigDecimal:7fbeccce7600,'0.1E1',9(36)>
1.9.3-p551 :045 > y = Marshal.load Marshal.dump x
 => #<BigDecimal:7fbecc8d8aa0,'0.1E1',9(36)>
1.9.3-p551 :046 > x == y
 => true
1.9.3-p551 :047 > Marshal.dump(x) == Marshal.dump(y)
 => true
1.9.3-p551 :048 > x.precs
 => [9, 36]
1.9.3-p551 :049 > y.precs
 => [9, 36]

Is this a bug? It feels like the unmarshalled value (y) in 2.1 could have different behavior than its original value (x), since the "maximum number of significant digits" (from precs documentation) changed.