Issue with marker layer symbology and symbology by attribute

[gauthierverlin]

Hello,

I try to create a symbology by attribute by varying the size of the lines according to the attribute " Ouverture ".
The function works very well when applied to single lines. However, when I apply it to a symbology that includes several layers (as below), it doesn't work as I want.

As you can see, instead of just varying the size of my line according to the "Opening" attribute, ArcGIS Pro varies the whole symbology (which is logical...).
 
On the left you can see the result on ArcGIS Pro and on the right the result I would like to have (obtained with QGIS)

Do you know a way to apply symbology by focusing an attribute on only one of the layers of a symbology?

Thank you. Thank you.