DATATERM

I recently migrated or better yet am still in the process of migrating from feddit.de to dataterm.digital. I really like it here and probably will stay here but I've been wondering about the difference in the "all" feed when comparing the 2 instances. On feddit.de's "all" feed I see many more new posts than on dataterm.digital's "all" feed. (I'm comparing sorted by new)

Can someone explain to me why that is and what's happening there? Shouldn't I be seeing the same posts regardless of the instances, given the instance isn't defederated?