@DallasD.Woodworks I had similar issues and also tried every suggestion I could find in these forums to no avail. I recalled reading about the changes in the SLB and firmware that they changed microstepping from 8 on the original longboard to 32. On a hunch I reverted back to 8 and seems to be working as expected now.
Seee this thread for the full discussion: Can SLB drive a stronger Nema 23 Stepper Motor? - SuperLongBoard / 
Question - Sienci Community Forum