I have a bounding box that is linked in properties that show all dim corretly. But, when I try to use the expression like: 

"SW-BoundingBox Length@@@@@Défaut@newtest.SLDPRT"

Inside another property, It returns the value corretly for a while but at some point it start to show the expression in the evaluated area. Its like the expression wont get evaluated but the bouding box dim are ok.

I use this because the expression get translated when switching to french-english so the values are always correct. If I use the property name, it return the expression inside the BOM if the language is different. So its working but dont know why it turn sometimes into unavaluated.

Thanks!

here picture of working and not working