Miller 255 wonder welder

Can Miller make a welder like they used to?
I am using tri-mix gas. Using a fairly new 400 amp Tweco gun. Was having sporadic issues with voltage spikes up to 47 volts. I was given a link to Miller's website for an update that came out in March that claims to fix the bug I was having. So I downloaded the zip file, extracted the contents to a thumb drive, ran the update successfully. Tried to weld some stainless and well, you see what I ended up with in the video. I use a spool gun for aluminum and that works really well. Other than the aluminum welding, this welder is completely useless to me.