I was getting a TMC error on my Prusa I3 MK3 on a particular part and it was related to a problem with their Einsy board. I got a free replacement from them, stellar support, and installed last night. I upgraded to the latest 3.4.1 Firmware and ran through calibration wizard like it was new. Calibration and self test all came back normal. The first layer tweak process they run through looked great too. Good adhesion, and good bead profile.
I went right to printing the part that led to the TMC error. I got into the base layer on what I consider a simple part and got the attached result. I printed one of the supplied Prusa demo files and it looked great. There's a small difference in the temperature between what Prusa's model uses (215C) compared to what Simplify3d likes (200C) but that's the only difference. I did notice that the Simplify3d part seems to run slower than the Prusa model did.
I have had this printer and using Simplify3d for 9 months and I don't recall seeing anything like this. I'm using a PLA Profile I've used before with no similar issues. I tried changing the z axis offset while printing and raising and lowering did not stop it from occurring.
This doesn't look like anything on the troubleshooting area on the Simplify3d knowledgebase site. Any ideas?