VBRS

When printing round shapes I get big blobs at the z seam, and in the case below I also get a irregularity left below on the picture. I printed this file several times and each time the irregularity happens on the same spot. So i have the following two questions: 1. How do i get rid of the blobs at the z-seam? (What I also see is that both wall layers are printed in opposite clockwise directions. I would expect less blobs if it would continue to print in the same direction per layer. Is this a setting I can change?) 2. Why is there an irregularity that keeps happening at the same spot? Specifications of the printer and model: - Ultimaker S5 - Nozzle of 0.8 mm (with a nozzle of 0.4mm there are no problems in this model. But I want to lower printing time by using the 0.8 nozzle) - Wall thickness of the model is 1.6 mm What i have tried so far: - Z Seam alignment to random -> Gives a lot of ooze and blobs - Enable coasting (with the 'standard' values that cura gives) -> No change - Increase the retraction speed -> Not a better result UMS5_Ontwerp 4.3mf