Given the input string "Ê̄ Ế Ê̌ Ề ê̄ ế ê̌ ề ", FontCreator preview incorrectly swaps the two marks above Ê̄ and Ê̌.These have different meanings in Chinese, and Unicode has specified that ordering of marks in the same group should be treated as ordered and could not be swapped.
Quote from https://unicode.org/reports/tr15/:
Multiple combining characters are combined with the base character.
g E-macron-grave E + macron + grave E-macron-grave
h E-macron + grave E + macron + grave E-macron-grav
Characters will not be combined if they would not be canonical equivalents because of their ordering.
i E-grave + macron E + grave + macron E-grave + macron
