Is it related to the homonym of grandson and grandfather's name?

yes. In the family, grandson's name can't use the same word as grandpa's, or even homophone. This is an old habit and out of respect for elders. If in some big families, when children name, there will still be such taboos. Otherwise, when they call their children, the elders agree. This is embarrassing and shows disrespect for the elders. Therefore, when encountering such problems, the children's names will be changed. There are so many words with the same meaning, and there is no need to use a certain word with the same sound.