Child ASIN’s Keep Separating From Parent ASIN

I have a year old parent ASIN with 6 child ASIN’s. Recently some of the child ASIN’s randomly came out. I re-add them and then about a week later they come out again. It’s not always the same child ASIN’s that come out. It’s random. I have contacted support and big surprise they are of no help whatsoever. Has anyone found a solution to this?