Ah, bless your granddaughter. My daughter is also Eurasian (German, Chinese/Malaysian). When she was in primary school in the UK, kids only noticed how petite she is rather than any colour and facial features difference. Now she’s 21 and we’re in Germany, she does get irritated that so many people immediately comment on how small she is and how young she looks. She recently politely responded to a middle aged woman ‘oh no, I never realised. Thank you for telling me!’ Her personality has grown to that of a giant!
When we visited an Hausarzt here, he immediately blurted out ‘obviously she’s adopted’. My daughter politely replied that she isn’t adopted and I’m definitely her mother.
The whole race row thing in the UK accusing an elderly lady of racism is just a storm in a teacup. People are naturally interested in others. Just some can be rude and condescending to anyone. It’s no different to any of us non native German speakers being asked where we come from. Surely that’s not offensive? I’ll never lose my British accent nor master German grammar. Quite a few Germans have said that they love to hear my accent though hate the accent of others.