[Soapy]

I'm fairly certain Magnetic Shield's redirect effect used to be applied earlier in the attack check, but that seems to have changed, possibly with the rework to Protect.

I know this is a very specific thing that only matters in certain fringe cases, but can it apply earlier on, before other effects (like Protect) kick in?

[Neus]

Protect doesn't apply in the attack check at all anymore, it applies well before it, just after the skill's target is confirmed.

So no, probably not.