Last week I received a nice email from @Kem_Ozbek where he informed me that they don’t see the same numbers as I previously posted 7d ago. He invited me to a chat where we would go through the numbers to work out a solution. 
Based on that feedback we started to investigate the issue further and have resolved an issue on our side which was created while implementing the Quality Assurance process using sync token before Christmas.
These are the accurate stats for the past 6h. 
So, Asana had its problems during 2021, upgraded 3 times in December, the week after those upgrades they had major issues. We couldn’t risk missing more events so we implemented a fail-safe quality assurance process using Sync tokens. While implementing that we caused our own issue, creating delays and missed events. As we saw Asana continuing with their maintenance and upgrades of Webhooks and event stream, we faulty assumed the issue was still on their side.
Asana is delivering webhooks and events with high quality and performance, and we are now happy with what we have. 
Thanks once more @Kem_Ozbek, @AndrewWong, and @Greg_Dardis for your upgrades and for the personal service that you provide when needed. 