Thank you for your reply's laszlo and DGSketch. So i double checked the connection handle and its not that, i checked PBC by switching materials and i discovered something "Interesting" with my AC19. (I'm using the student´s 1 year version.)
The type of operation i want to generate is a subtraction with an upward extrusion.
The thing is when i insert a Simple wall (First yellow wall in the image) and try SEO, it doesn´t do anything. I tried switching to a Multi-Layered Wall (Second red wall in the picture) it does respond to SEO, and the third wall is a copy of the second wall but
after i applied SEO i switched it back to a simple wall and it seems to still respect SEO.
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Okay, i just found out the problem for my issue...
I will still post this "Just in case" if any other user is having the same problem.
You were right, it does have to do with the type of material and the strength of the material, i switched the simple wall to concrete or brick, and the slab to another type of concrete, and now it works perfectly.
Another thing is that i have 2 types of libraries linked to my AC,
spanish version and
english version. So as a result i have a mix of materials when selecting one, some of my walls are using "Hormigon" (Equivalent to Concrete in Spanish) and others are using "Concrete". Same goes for slabs. So i guess first i will make sure to change the material type to either Spanish or English type and then i will double check the materials for my walls and slabs.