Bug: Hallow (all spell damage prevention maybe?) does not comply with 400.7b

Bug from Discord.
> [[Hallow]] Should be able to prevent damage when targeting a permanent spell (creature for example, so etb dmg or combat dmg i.e.) In my case it didn't prevent Atarka's (the double strike dragon) damage, or the dragon tempest trigger when it entered.

From the rulings:
> 400.7b Prevention effects that apply to damage from a permanent spell on the stack continue to apply to damage from the permanent that spell becomes.

I'm not sure if we partially comply with 400.7b, or not at all?

[[Dragon Tempest]] [[Atarka, World Render]] [[Dragonlord Atarka]] (not sure which atarka, one has a damage etb, the other has double strike which was mentioned in the report)
I didn't attempt to replicate the bug.

Start by reproducing the report with Hallow, Dragon Tempest, and the relevant Atarka card, checking damage from both an entering permanent and combat. Compare the observed behavior with rule 400.7b and determine whether prevention applies after the spell becomes a permanent. Done means the reported damage-prevention cases comply with that rule and have regression coverage.

Written by the indexing model from the issue text.