Looking at the daily number of page creations suggests that there's data missing in the underlying datasets. I've manually checked some of them and it looks like the count is low for Jan 3, 2018, and missing for Jan 4–6. Data appears to exist in the log database on analytics-slave:
SELECT DATE(rev_timestamp) AS log_date, count(*) AS num_pages
FROM mediawiki_page_create_2
WHERE rev_timestamp >= '2018-01-01 00:00:00'
AND `database`='enwiki'
GROUP BY log_date;
+------------+-----------+
| log_date | num_pages |
+------------+-----------+
| 2018-01-01 | 7346 |
| 2018-01-02 | 8404 |
| 2018-01-03 | 7768 |
| 2018-01-04 | 7756 |
| 2018-01-05 | 7184 |
| 2018-01-06 | 7358 |
| 2018-01-07 | 7672 |
| 2018-01-08 | 8311 |
| 2018-01-09 | 8949 |
| 2018-01-10 | 8154 |
| 2018-01-11 | 7843 |
| 2018-01-12 | 7709 |
| 2018-01-13 | 7299 |
| 2018-01-14 | 7382 |
| 2018-01-15 | 8076 |
| 2018-01-16 | 6091 |
+------------+-----------+
16 rows in set (0.52 sec)Maybe the solution is to delete all the TSVs and recreate, since there's not that much data?