Vertical walls not sticking to one another

[bkirkby]

I am fairly new to 3D printing and not sure what the correct terminology is. The problem I am having is that my walls (perimeters?) are not sticking to one another. At the top of any wall, I can run my fingernail across the top edge and pull the wall sections apart. See the image for an example. I think the issue could be under extrusion but I have tried the print on two different printers, and one of them is almost brand new and has a micro swiss geared direct drive. Both printers give me the same results. I have tried several things like slowing the print down, increasing the temperature of the PLA, changing wall thickness, changing z-seam to "shortest" - I have tried the same 3mf and stl files on both Cura and PrusaSlicer. I am at a loss for what is causing this to happen. Has anyone had this happen before? I am creating my files in Fusion 360. My two printers are an Ender 3 pro and an Ender 5 Plus. Thanks in advance for any help.