MS has been holding a few briefings recently too, hence the leakage. The 12TF/4TF numbers are being backed up by Tom Warren (The Verge) on Resetera and linked back to previous tweets he made.
When questioned on that on Resetera he said this too …
mmmm teraflops. Maybe it’s 12, maybe it’s 4. Maybe it’s both? The teraflop mystery continues.
https://www.resetera.com/threads/next-gen-ps5-and-next-xbox-speculation-launch-thread-ot7-nm.148625/page-91#post-26464801
This was all prior to yesterdays leak.
Now a further interesting point on where PS5 sits in this equation. This is what Tom wrote pre-E3, and others have also suggested in pure TF terms PS5 is slightly ahead. This would put PS5 13TF. The difference between the two being minimal. At those levels everything else like games, services, eco system, experience will matter more to everyone but Digital Foundry.
Got to say if true those numbers are great. When comparing to vanilla PS4/X1 the performance will be more like 16-17TF. :-O