I'm using magento2.2.5, setting the default meta description from design configuration then setting each catalog category meta description individually, then clearing the cache but the default meta description still displaying in the category page. Am I missing something? How to solve this?
If their no customization then there is only one case when category meta description is coming from the default meta description.
If you might be set meta description of that category field at All store view label, At your store view label, the value is set as blank.
To check, open the category page at admin, there is drop field Store View on the top left corner of that page. From this drop change to Default Store View or your store view and see what Value set That Meta Description.