Google Search Console cannot find all sitemaps in the sitemap index. How to fix?


I created a valid Sitemap index (/sitemap-dec2019/sitemap_index.xml) for a site as follows:

    


https://www.example.com/sitemap-dec2019/sitemap1.txt
2019-12-10T18:24:17+00:00


https://www.example.com/sitemap-dec2019/sitemap2.txt
2019-12-10T18:24:17+00:00


https://www.example.com/sitemap-dec2019/sitemap3.txt
2019-12-10T18:24:17+00:00

.
.
.

https://www.example.com/sitemap-dec2019/sitemap536.txt
2019-12-10T18:24:17+00:00


Each Sitemap Child is a simple list of 49,999 URLs and they are all less than 10MB in size.

I uploaded the sitemap index and all the kids from the sitemap to the server. I double-checked to make sure the sitemap index and all sitemap children are accessible on the server, and are.

However, when I submit the Sitemap index to Google via Google Search Console, I get a success message saying "The Sitemap index was processed successfully", no errors are reported anywhereAnd yet it only lists 9 out of 106 Sitemap Children (and they all start with & # 39; sitemap1 & # 39;):

Sitemap                         Status  Discovered URLs
/sitemap-dec2019/sitemap1.txt   Success 49,999
/sitemap-dec2019/sitemap10.txt  Success 49,999
/sitemap-dec2019/sitemap100.txt Success 49,999
/sitemap-dec2019/sitemap101.txt Success 49,999
/sitemap-dec2019/sitemap102.txt Success 49,999
/sitemap-dec2019/sitemap103.txt Success 49,999
/sitemap-dec2019/sitemap104.txt Success 49,999
/sitemap-dec2019/sitemap105.txt Success 49,999
/sitemap-dec2019/sitemap106.txt Success 49,999
1-9 of 9

There is nothing different in the Sitemap index that causes Google to select only those 9 specific Sitemap children.

In total of URLs discovered, it says 449,991 which turns out to be 49,999 x 9.

When I remove the Sitemap and re-add the Sitemap Index, the same 9 Site Map Children appear on the list, and none of the others appear anywhere.

Considering that there are over 100 Sitemap Children, this means that over 90% are being completely ignored.

How can I fix this so that 100% of the Sitemap's child elements (and their respective URLs) are discovered?