Jann Horn's results & report pre-date the blog post though. The topic was "ripe", so to speak, so multiple parties investigated it at roughly the same time.
Yeah, the blog post says they knew since June 2017, with that blog post being from July.
> This initial report did not contain any information about variant 3. We had discussed whether direct reads from kernel memory could work, but thought that it was unlikely. We later tested and reported variant 3 prior to the publication of Anders Fogh's work at https://cyber.wtf/2017/07/28/negative-result-reading-kernel-....
AIUI, Anders Fogh has collaborated with people at TU Graz on various occasions previously: I'd assume they already knew about his work prior to the blog post.
> This initial report did not contain any information about variant 3. We had discussed whether direct reads from kernel memory could work, but thought that it was unlikely. We later tested and reported variant 3 prior to the publication of Anders Fogh's work at https://cyber.wtf/2017/07/28/negative-result-reading-kernel-....