Subtable with colspan and multi-line text breaks across pages

[tbates-redarc]

This is the smallest example I could produce:

require 'prawn'
require 'prawn/table'

pdf = Prawn::Document.generate("sample.pdf") do
  subtable = [
      [{content: "Colspan 2", colspan: 2}],
      ["Column 1\nLine 2", "Column 2"],
    ]

  table([[
      subtable,
    ]])
end

The second row of the subtable gets spilled onto a second page, and overlaps with any content that might be on that page. Removing the colspan or the \n makes the problem disappear.