Crazy. I can't remember an incident like this ever happened before and it's still not fixed? .de is probably the most important unrestricted domain after .com from an economical perspective. Millions of businesses are "down".
DENIC apparently resolved all .de domains to NXDOMAIN in 2010: https://www.theregister.com/2010/05/12/germany_top_level_dom...
There's a good index of major DNSSEC outages here, https://ianix.com/pub/dnssec-outages.html
It's Germany, pessimistic time estimation + 1/3 and you are in a realistic time frame for the issue being resolved.
Well it was already very late in the day (21-22?) so the impact was not big I would say
I remember when .com went down, in July 1997.
https://archive.nytimes.com/www.nytimes.com/library/cyber/we...