2004 5 cent - dent on cheek

There seem to be a few "unidentified dents" on the obverse of the 2004 coins.

I thought that grease would spread if squashed, but the dent is relatively deep, so I suspect it was some other material.
I have been trying to work out why these 2 coins have a dent in a similar place, and I have worked out a theory.
Does anyone know how the dies are arranged during production?
If the obverse die faces up, anything falling into the production area would fall into the obverse die, and since the queen's cheek is deepest, it would tend to fall there.
That might explain why these 2 coins have a dent in a similar place.
How does that explanation sound?