I agree, I've never seen that is an allowable treatment.  Publication 929 even shows what to do if the parent's information is not available, which seems to imply the Kiddie Tax still applies even if the parent is 'in the wind'.

https://www.irs.gov/publications/p929#en_US_2020_publink100036257

I agree, if the Social Security payments are in the name and Social Security Number of the child, they go on the child's return.  But check the Social Security Number on the SSA-1099 to see whose number it is.