Creating a chart that aggregates edits tagged with a certain subset of edit tags results in additional tags being shown in the chart. From what I can tell it appears that aggregation occurs for all tags that the edits might be tagged with (e.g. "mobile edit' and "mobile web edit" for edits on mobile). This results in a very confusing chart.
See http://superset.wikimedia.org/r/140 for an example. I'd expect the chart to only show weekly edit counts for the 4 selected tags: "help panel question", "help module question", "mentorship module question", and "newcomer task".