Actually, i looked at the files and either Ame confused herself (I doubt it) or she did it on purpose.
I believe on the latter. And if you're wondering what i'm talking about:
Paras/Parasect have a 1% chance that they will hold a Balm Mushroom. And based on Gen V wild held item table, they should do that only in dark grass. But, it's coded to happen in Reborn anyway.
Heatmor on the other hand, doesn't have a chance that it will hold a Flame Orb. The reasons for that:
1 - It's technically not wild since there's only one (But then again, remember Elekid? Yeah...)
2 - Ame forgot (Pfft...)
3 - She did it on purpose since Flame Orb can be a powerful item in the right poke.
I'm going to look at the files again, but keep what i said in mind. Maybe Throh and Sawk can't hold an Expert Belt, since it's a very good item also.