@miniature-kangaroo-6093 no that was the only issue. A similar thing happened in the other prod environment that I upgraded but I had recently added a couple extra Longhorn nodes to better balance the replicas across nodes just an hour or so before. It's possible that was from auto-rebalancing, but it did seem to start happening when I upgraded Rancher, so I'm not entirely sure why it happened.
The data was fine, but that might not be the case if that happens to all 3 replicas of an attached volume.