I purchased a Hisense 55H8F TV from Best Buy back in 08/2019 (08/02/2019 to be exact). Recently, I've been having problems with the TV - the wi-fi on/off setting (in the Settings menu --> Network --> Wi-Fi) keeps turning the wi-fi capability of the TV off while the TV is in standby/off. I don't know if this is a result of a firmware update that may have occurred or if it's a hardware failure that may not be repairable.
To explain further, last night I was using the TV. It was connected to my home wi-fi network, everything was working well. Using the remote control, I powered off the TV. I left the room to go eat dinner - no one was in the room for this time period. After dinner, I went back and turned the TV on again. As soon as the screen came on, the TV displayed a notification across the top that "the wi-fi setting is turned off" (or something to that effect). This has happened 5 times so far this week, so it's not just a fluke. When I get this notification, the only way to get wi-fi back is to go into the TV Settings --> Network --> Wi-Fi and manually toggle the wireless functionality back to the on position. Consistently when I do this the TV will immediately find and connect to my home wi-fi. I have tried everything from switching the TV's wi-fi connection back and forth between the 2.4GHz and 5GHz bands, factory resetting, checked for all firmware/app updates, all to no avail.