This is a feature  to make it easier to troubleshooting a terminated instance. Track Tokens takes a snapshot of specified tokens at the time the activity runs. But if you don't happen to have a Track Tokens activity in the right place, those values might be out of date when you troubleshoot a terminated instance. So we record all token values at termination time. Similarly, when the workflow is run manually from the Designer, we also track all tokens when the instance completes (successfully or not) because the general use case for running a workflow manually is that you are either making changes or troubleshooting.

In the instance details, you can see the different sets of tokens if you have multiple Track Tokens activities or a combination of Track Tokens. There will be a drop-down list in the top left side of the pane so you can narrow down your list to individual Track Tokens activities.