One of the changes mentioned in the patch notes was that the backdash was more vulnerable. I decided to test this using PStick setup.
Astaroth does standing A (long reach, hits fairly consistently on its first active hit frame regardless of distance, simple motion, known frame data).
Taki presses 4 or 454 (1F for each input) then holds guard.
Assuming the first input occurs on F0,
If Taki enters 4 on F0, then holds guard from F15-30, while Astaroth's standing A hits on F20, it will not be guardable.
If Taki enters 4 on F0, then holds guard from F15-30, while Astaroth's standing A hits on F21, it will be guardable.
Same applies to 454, with respect to the initial input (e.g. 4 on F0, 5 on F1, 4 on F2) suggesting that the frame data relates to the initial backwards input.
Mediafire upload to come, so that people can check this for themselves.
If a mod could fix the typo in the topic title, that would be great.