Hi there! I’ve only had my GF Pro for 2 weeks but I had a problem and wanted to share in case it may help others.
Yesterday all my cuts were great. My first cut today has serious wobbling in any line running horizontally. I poked around under the lid and found that one of the wheels on the plate that holds the print head was off-center. Looks like the bearing or something has gotten off axis. I wrote to customer support and am awaiting a resolution.
So, if you have wobbly lines like this, check the wheels!