I know it might sound too “critical” but that tip/nozzle is losing its roundness. Compare it to a new one.
I once had a nozzle, that I swear was perfectly round. I was having trouble so I compared it to a new one and it was definitely showing the wear. The new nozzle fixed the issue.
I am not sure on the SYNC version but on the standard Hypertherm nozzle there is a step inside. I will try to find a cross-sectional view, but inside, the channel is slightly smaller than the outside profile. Once the step is worn down, it is a totally different plasma operation.
Here is the picture from Tin’s post:
