Maybe the spike moved?
I saw a few GD creators (especially Vortrox) die to a spike that moved away from their icons. They had reactions like: "How did I die there?"

skill issue
/unsrs

easy
the hitbox that youre seeing is the one that rotates with the cube. this one means nothing. it is purely visual.
there is also another square hitbox that doesnt rotate. this one seems to be invisible. this one actually counts as a real hitbox.

so in conclusion, your real hitbox collided with the spike.

The not rotating one is only responsible for things like portal interactions to keep them consistent, the rotating hitbox is the one responsible for deaths

Yes

you jumped early

in-game hitbox viewer doesnt show the actual collision hitboxes, try using megahack or something similar, those show the real ones

Inaccurate hitbox

accurate hitbox