It’s not top thickness, that’s only 3 layers and the bulge is on more layers than that.
Printed with PLA, 4 perimeters, 15% gyroid, but no infill makes difference, i don’t think this is about shell thickness.
Retraction is good, there is no oozing on retract moves and no stringing on the printed parts.
Otherwise the prints come out okay so i’m a bit stuck with this one!
You can see the bulging in all three edges on the picture, about 3-4mm from top to bottom, then a few ok layers, then again a few layers with bulges on corners.
Slicer is Prusa if that’s relevant.
Any ideas are welcome!
Eh, sadly can't help too much with that. Used to have an Ender 5, but got an Artillery X2 gifted (aye...), and since then have been using that due to the combination of direct and the larger print bed (even though I conceptually don't like bedslingers due to the large footprint they have). And I had the Ender 5 too briefly to dial it in much.