This is not an idea. It's a bug. When opening Indesign files built in CC 2019, from either the INDD or IDML file, often times the stroke style does not translate properly.

For example, often a line or a shape with a 1px Black stroke will import with no stroke at all.

I have never had this sort of incompatibility with IDML files in the past. I do not use CC 2019 because it hangs on every move I make.