Vice-Presidents, especially those who haven't served in Congress themselves (Pence was in the House) are legendarily bad as presiding officers, which is why they rarely do it any more except for ceremonial occasions or when needed to break a tie.

The worst case was an incident that happened to Charles G. Dawes in the 1920s. Not expecting a vote, he'd gone home to take a nap, and couldn't be fetched back in time to prevent an appointment losing on a tie vote. That pretty much left his name mud in the White House.