The Senate ought to demand one.
The dems are saying that they’ve released the articles of impeachment and that the Senate can act on that.
But if they are not formally delivered the official final copy, the House Dems could later turn around and claim that what the Senate took from whatever source it had, was not the OFFICIAL final version of the articles of impeachment, therefore the whole Senate hearing and vote was invalid and needed to be repeated.
They can claim what they want - the Senate has the sole power to try impeachments according however it decides.
Link?