I've noticed that the Mag Ferro helmet seems to default to a dark blue color, and when a copy of your customized frame appears in other places in the game, it defaults to that color instead of your chosen energy. So far I've noticed this in two places:
After using the True Master's Font, when the statue changes to match your frame
In Teshin's Cave in Duviri, when Mag is selected as one of the frame choices.
Interestingly, I've noticed that when customizing Mag's appearance with the Ferro helmet equipped and default colors selected, changing almost any other part of the frame causes the helmet color to snap to that same dark blue for a second before reverting to Mag's default yellow, even if you're not changing anything about the helmet itself. I'd hazard a guess that anything that causes the frame to be re-rendered is making it default to this color? So far I've noticed this flickering behavior when doing the following things, so long as the frame's colors are completely default:
Resetting frame colors to default
Changing skins
When choosing any color, moving the mouse off the color palette
Selecting some attachments from the list to preview them (armor, ephemeras, syandanas, emblems)
Toggling prime details on or off
Clicking into almost any customization list to choose a customization (helmet, skin, animation set, armor, ephemera, syandana, emblems, sigils)
I will try and capture some video and images when I have a chance later.
Edit: Mag came up in my Circuit rotation, so here's how she appears in the preview:
And here's how she appears after selection, with the correct energy color:
Had the presence of mind to capture pics for the True Master's Font as well. Before: After: