Google Search Console page indexing report missing data prior to December 15

This seems to be impacting everyone - so it is likely a Google reporting bug.
Search Engine Roundtable

Ongoing Google Search Console API Bug Impacts Search Appearance Filter

Google Search Console has a bug with its API when filtering on the searchAppearance dimension. This bug occurs when using the notEquals or notContains operators, it will only return rows with the ...

Google SEO tools review

Google’s SEO tools, including Analytics, Search Console, and Ads, are a powerful, free way to build your website traffic.