Brand new Yamaha EF6300iSDE instant overload (with video)

Can any of the people that posted on here having the same issue test their 6300 with a multimeter to determine the hot? I checked mine again last night just to be sure and it's 100% opposite of the 3000 Yamaha inverter. If you're looking at the 30A receptable with ground at 12 o clock. The hot is clockwise around 4 o clock on the 6300. Which lines up with the silver prong of my plug in and is exact opposite of the 3000. I've tried contacting Yamaha. My dealer contacted his rep and he's never heard of any issues like that but said it could be wired incorrectly. What's strange is others have had exact same issue so is it likely that a whole batch of them were wired incorrectly? For now, I bought the 120/240 4 prong plug and just hooked up 1 hot line so I"m running 120 only. It's wired correctly and is working fine. I guess if I just don't use the 30A 120 receptacle that's an option but it still bothers me and would like to understand the issue. Thanks.

Just wanted to update this thread.

No matter what parts were replaced on the EF6300iSDE, we could not get it to work. We returned it & brought home an EF4500iSE (just like our old unit) & it works perfectly. After talking to a couple electricians it is suspected that the 'split phase' nature of the EF6300 (120/240V) might have been the issue.