I choose to believe there is a lot more to the magic object than the truth or it’s own will. It’s a mirror after all, what you see depends on who stands before it. If you ask to see beauty and the reflection shows how you compare to a 14 year old, that’s on you.
Then again, when have these things ever been static. Shrek’s iteration has it’s own will.
I know, that’s what my “when have these things ever been static” was supposed to express.