It was then that the presiding officer, President pro tempore Patrick Leahy, showed first that he's not a good parliamentarian, and second that the tradition of treating the President pro tem as a mostly honorary position who rarely actually presides and who is normally the most senior member of the majority party is possibly not a very good one. It appears that the Senate Parliamentarian wasn't expect this, and fed Leahy a ruling. Also unfortunately, he apparently wasn't working well with his microphone and the natural muffling of his face mask combined with him not being apparently a very forceful speaker meant that people had trouble hearing him. The ruling seems to have been that the Senator's objection was not in order due to a certain rule adopted for the trial (I couldn't quite follow it myself), and that ruling was appealed. Leahy proceeded to try and put the appeal to a vote, but the Senators, quite rightly in my opinion, raised an uproar because they didn't even know what they were voting on.
I do not know the specific rules adopted for the trial, nor do I know what the Senate's rules regarding appeals of the chair's rulings are, so what I say here is based on general American parliamentary procedure under Robert's Rules of Order, Newly Revised. Bear in mind that RONR traces back to the rules House of Representatives, and Senate procedure is different. However, had this happened on my watch, it appears to me that this was a debatable appeal, not something that would have to be put to a vote without debate. But the biggest problem was not letting the Senate understand what they were supposedly considering.
I am not a perfect parliamentarian. There have been multiple times that I've gotten into parliamentary snarls. However, at least most of the time I have tried to make sure that everyone in ever meeting over which I have presided understands what it is that they're voting on. I've been known to stop a vote and roll back to the start of voting when it becomes clear that people don't know what the question is. How can you have a fair vote if you don't understand the question?
In addition, WSFS presiding officers are usually accomplished parliamentarians in their own right, rarely needing a Parliamentarian's direct advice. For the past few times I've presided, I have asked Donald Eastlake III to be my Parliamentarian and have tasked him with doing the on-screen slides that have usually improved the ability of the meeting to follow what's going on. (Donald is of course an experience presiding officer, and I've been his deputy and/or Parliamentarian in other years.) And of course, the matters we consider, while important to us at the time, is much less weighty than the question currently before the US Senate.
In this case, after an uproar and a quorum call (done to put action on hold while people conferred), the House Managers agreed to withdraw the sections of evidence to which the Republican Senator objected, although they reserved the right to re-litigate the matter tomorrow. Presumably if they decide to do so, the Senate Parliamentarian will have enough time to prepare her advice (which is rarely rejected by the Chair) so the question before the Senate will be comprehensible.
I'm afraid that President pro tem Leahy is okay for the simple stuff of calling the Senate to order and recessing and adjourning, but he certainly seemed out of his depth this afternoon.
Edit: I somehow managed to originally write this referring to Chuck Grassley (the previous President pro tem) instead of Patrick Leahy. The same criticism applies regardless of which party holds the job. Treating it as a ceremonial post of little significance is not a great idea in my opinion.