I don’t know but why would they do that unless there were new charges?
I don’t think this could go much better for Dems than polls showing half the country favors impeachment a week into the process, the WH obviously flailing and obstructing, the House lays the evidence out and controls the message while Dem candidates run a collegial primary, impeachment becomes more popular by the week, and then Moscow Mitch completely stonewalls the conviction. The Dems want to run against that party. The GOP would be completely exposed for who they are.
Honestly, I think this will last awhile because no way Ukraine is the only place Trump and his cronies are trying to enrich themselves. More will turn up.