Same as for me.
My daughter finished PN and went to another school for K1. I applied the same school (same campus) for my younger son. I wrote down that my daughter has studied here and left for another school, which is the fact.
I went to the school and submitted the form personally. I even talked to the principal...however, she asked me not to worry as they usually accepted sibling...sigh. I guess she forgot my daughter has left.