Did you receive the email I sent you last Friday (July 22nd) regarding this? It read:
“The LOTOS LTP5500D is one of the specific plasma cutter models that we do not recommend using with our CNC machines. Interference generated by the power supply of this model has been known to cause issues with CrossFire electronics. Use of this plasma cutter model is not supported by us, and is at your own risk.”
To be clear, you are correct that the LTP5500D does not use high-frequency start - @langmuir-aksel’s comment was referring to the LTP5000D, which does. The incompatibility of the LTP5500D stems from it’s power supply.