[Update 8/19/2017]
SNK has officially announced that Fuzzy Guard/F-Shiki wasn't intended to be in KOFXIV and its developers are currently trying to fix the issue. There will be a patch when the team figures out how to get rid of it.
The Free Demo for KOFXIV has been released in most regions of the globe and with many players rummaging for tricks and high-damage options, it isn't surprising that a common classic tech from other fighting games has been discovered.
For possibly the first time in the KOF series,
Fuzzy Guard has been confirmed to be in KOF XIV. Rumored since day 1 of the demo's release, seasoned Japanese player Dune has posted up an example with Iori and Mai.
Fuzzy Guard (aka F-Shiki in Japanese) is a technique involving a programming design in blocking.
In a nutshell, when the player stands to block an opponent's jump-in and then blocks low, the opponent can immediately do another jump attack and it hits as an instant overhead. This is due to an issue in programming design where the hurtbox from the standing position will still linger for a short time when the player goes into crouching position.
Fuzzy Guard is found in many fighting games including Arc System Works titles and even Street Fighter V, but for KOF14 in particular it seems to be much easier to do since a blocked jump CD leaves the standing hurtbox active for a relatively long time. For characters that can combo off their jump attacks, this may potentially be an extremely useful move.
Given that this is only a 7 character-demo, it's still not certain how Fuzzy Guard might be abusable in the long run if it ends up unpatched and remains as a part of the game's design. For the example video, check below.
https://twitter.com/Dune_KOF/status/755781983762984961