After have a saphire and aquamarine eternity band sized, 3 aquamarines appear clear, when before they where a very pretty light blue. What might cause this? Thanks for the help

Low grade aquamarines are heat treated to make them appear a more intense blue. Could be, the effect is wearing off and that's why the colour is changing.

A real aquamarine will never lose its brilliant blue colour.

Tick

My guess is that the heat used to resize the band leeched the color out. Many stones change color under heat, some get brighter and others lose their color. Some stones can even do both, depending on the degree and duration of the heat.

If exposed in the sun or heat, aquamarine tends to loose its color. Hence aquamarines are advised to keep in dark places.

Jewelry is re-sized by subjecting it to heat. Your stone has lost it's color because of resizing the band.