Yeah in BfA it was wonky, it depended on the spell. Chaos Bolt for example did hit you if it was in the air.
Blizzard has a lot of spaghetti code going on with this, especially Chaos Bolt.
I dunno, I only hate the inconsistency with this depending on the def CDs… Dispersion, Turtle for example don’t work if the spell is already in the air, but most other things do.
To me, it should be that way for every defensive that the spell goes through. (Except full immunities of course, including CoS) You failed to react in time BEFORE the spell finished casting, so it’s on you. Allthough I believe this should ONLY work like that for spells with a cast time. Instant casts should be eaten… but oh my what crazy work we’d expect of these devs to actually implement this…