Mostly 10mm as that is what I make the most of but has been happening on 12mm and 14mm. My 12mm and 14mm are 40 cavity and 5 per string. It is always an entire string of eggs that turns. They are clear when they come out, but over a period of time, usually a few weeks, I wake up, and bam, they have changed. If they were coming out of the mold opaque, I would not package them with the clears.
Of note, I have a couple other colours: MF Jelly Red (transparent but doesn't bleed) and Dels Shock Orange (Transparent but does not bleed) and am having no issues with them changing colour.