The tags in the old UI used to be at the bottom of the ticket properties. Now it is at the top of the conversion thread and once there are a few replies, tags are by default, not visible. So adding to them requires a scroll to the top of the message thread. This is super inconvenient once the thread gets long.
Please relocate the Tags to somewhere more easily reachable. Perhaps just put them back in the properties pane where they used to be and IMO, where they belong.