I had a phone screen with the recruiter and two pair programming sessions done via CoderPad.
The pair programming problems I got weren't from leetcode, but they were very much in that style. They weren't very difficult, but there were multiple steps so it does take a bit of time to complete.
Feedback from the pair programming sessions leaned negative, which surprised me since I thought I did well and I was able to demonstrate that I clearly knew how to code. My coding style is to code a rough skeleton of he solution, then run the program with some fixture data and make adjustments until it's working, a bit like TDD.
However the interviewers didn't seem to like that approach and the feedback largely focused on how when I ran my program, it had bugs. Not that the program had bugs and I couldn't get it working by the time the interview ended, but that it had any bugs at all when I ran it, and fixing those bugs was seen as me "struggling" to get the program working.
If I were to have the opportunity to interview at Square again, I honestly have no idea how I could do better other than to code out a near-perfect solution that worked on the first try. Making it past this stage of Square's interview process seems like a complete roll of the dice. When the goal of the pair programming session doesn't seem to be to solve the problem, and even small errors are enough to doom your candidacy, it's difficult to see what the point of this exercise is or how you're being evaluated.