Preview okay, but no data scraped

Describe the problem.
This page has links to subpages. It has a "load 10 more" button to asynchronously load more data. I want to extract the links. When I run the Data Preview, it shows the links. When I run the scrape, it pages through, 10 at a time. The monitor page remains at "no data scraped yet". At some point, the scrape ends and the scrape window closes (and I don't know when because there is a lot of data and I haven't seen it close). The monitor window remains at "no data scraped yet".

Url: https://www.fitbit.com/activities

Sitemap:
{"_id":"fitbit2","startUrl":["https://www.fitbit.com/activities"],"selectors":[{"id":"clickmore","type":"SelectorElementClick","parentSelectors":["_root"],"selector":"section.activity-history","multiple":false,"delay":"7000","clickElementSelector":".load-more span","clickType":"clickMore","discardInitialElements":"do-not-discard","clickElementUniquenessType":"uniqueText"},{"id":"activity_links","type":"SelectorLink","parentSelectors":["_root"],"selector":".view-exercise a","multiple":true,"delay":0}]}

Load More can be tricky and is not that intuitive to set up. There is a very good tutorial for "Load More" from the WS team at:

The "Load More" bit actually starts around 5:12, but you should really watch it all the way from the beginning 'cos it explains important concepts such as wrapper elements, element selection, child selectors, etc.

BTW, this same video also covers "Infinite Scroll" at around 3:25.