Absolutely right, commented on also on the discussion page for the English-to-Turkish form.
In both cases, the error is not reportable. It's funny that when the system accepts your translation it does not allow you to report that theirs is wrong. That is a programming flaw and one sees many examples of such non-reportable errors on the forums.
In sentences with -ken we understand the pronoun from the part of the sentence without -ken.
So in this sentence "Üç yaşındayken göz ameliyatı oldum" we understand "I" becuase of "oldum".
But what we do with sentences like that, for example: "When I was three my parents got diorced"?
"Üç yaşındayken ebeveynim boşlanlardı" ?
How do I know that "Üç yaşındayken" means "When I was three", "When he was three" or "When your were three"???
When I was three my parents divorced : Ben üç yaşındayken aileM boşandı. (From "m" in "aile") When he was three my parents divorced : O üç yaşındayken (benim) aileM boşandı. When you were three my parents divorced :Sen üç yaşındayken (benim) ailem boşandı.
We add necessary subject, if it is not clear and we add possessive pronoun to the second part to make it clearer.