1-1 Association returns empty though it has just been filled

I have an dossier entity where I sometimes to add notes to.

When I open a page to write the note, I first call a microflow where I create an object for the note and associate it to the dossier object via a 1-1 association. When I open the dossier object in a dataview and try to retrieve the 1-1 association (which I just created in the microflow) in another dataview, it returns empty. However, when I fill the association from the dossier object, it suddenly works. When I fill the assocation from both sides, it doesn't work either.

I thought it didn't matter from which object you fill a 1-1 association. Does it?