The domain https://fediverse.observer/ redirects to sedo now.
On October 11th these two commits where made to the repo:
this will be my final release, glad to have contributed since 2011 to some fediverse stats, https://fedidb.com/ is a great resource with more interest
this software is no longer developed
Sad to have lost such a great resource.
Have you contacted them about the discrepancy? Ideally FediDB could just become the new Fediverse Observer.
Missing out on accurate data about Fediverse growth would really suck. 😕