Obviously defective and not worth even thinking about fixing it yourself. If you could return it then probably do it quick.
Hisense is straight garbage. I got two Hisense tvs in a row that the screens just went out within a month and basically had to fight to return the last one. Their customer support never got back with me. Ended up with getting a Sony display model half off.
I have the same issue with my Samsung TV but it started after 5 or 6 years of owning it. If I use it regularly it's fine but I'll leave it off for more than a few days and I get that issue. I would exchange it if you still can.
I was having the very same problem with a Vizio 55 inch. Before taking it back, I tried a better quality HDMI cable and it never did it again.
Did you try unplugging HDMI cables (one by one) to see if a device is waking up the TV?
I believe BestBuy pulled the Hisense off the shelves because of an issue with android.
Faulty T-con board
Buy Lg next time. It will last 10plus years.
Smells like a Chinese brand
Have had the same Hisense smart led tv for the last 8 years. Not one issue. Always worked and been a great picture. Would buy Hisense again. I'm actually looking at upgrading to a 120hz 4k Hisense. Every brand has faulty devices.
If you can return and change it while it's still possible then don't waste any time and do so,
You don't want to take the risk of having a defective TV if you can return it.