The cut-line are not complete - not closed

First, is the sheet the same size as for car graphics? Just double checking that the ones that are giving you issue fit on the sheet. If it's close then that small margin could be causing the issue. I normally try and "poll" the plotter if the sheet size changes to make sure it is all fitting on the sheet.

I had a similar problem to yours using Flexi-Sign software and it took forever to figure out because it was so random. Still not sure why it does it sometimes and not the other but within my software I have a "Panel Size" setting in the production manager. The margins are normally set to 0.000inch so I changed that to 0.050inch and it fixed my issue. Not sure if you even have that setting in your software but figured I'd provide some input just in case since I know trying to track down problems that are random can be frustrating.

 

The sovereign remedy for this sort of malfeasant cutting is to remove any dust cover on the plotter tool carriage and blow all the dust and crud out oft the meachanism paying particular attention to the tool up/down mechanism. It doesn't take much contamination to affect the timing of the blade transport mechanism making it just a wee bit slow to respond.

 

set a larger blade offset