I finally had a chance to dig into this one. As far as i can tell, English-language SVG maps is not excluded in the first query, but is explicitly added as an exclusion in the second query. So the result descripency is likely to be due to this addition.

We can look at the query dump as see that English-language SVG maps is not part of the categories exluded in the first query. only English-language SVG maps of the world and English-language SVG maps of the world by Our World in Data. I tried to look around and understand if this is the correct behaviour, as far as I can tell it is.

The parent categories of English-language SVG maps are SVG maps by language English-language maps English-language SVG
The parent categories of SVG maps by language are SVG maps Maps by language SVG by language
The parent categories of English-language maps are Maps by language Legend in English
The parent categories of English-language SVG are SVG by language English text

If we adjust the second query to exclude English-language SVG maps of the world instead of English-language SVG maps we get matching result counts of 1086 for both:

-deepcategory:"Maps of the world by language" deepcategory:"2020s maps of the world" -deepcategory:"Wikimania Map of the world" -deepcategory:"SVG maps of the world by language" -deepcategory:"English-language SVG maps of the world" -deepcategory:"Our World in Data food and agriculture maps of the world"

I put together a self-contained .html page that will request the querys that are executed for two different deepcat queries and report on the differences in categories that will be included/excluded:

• reported queries
• potentially corrected query