I wasn't watching TNT last night, though my wife does watch a couple of shows on the channel at times. I was the originator of this thread a couple of years ago, and I had commented more than once about the buffering issues that were a constant problem. But Sling has made a lot of improvements since launching and I rarely have any problems, buffering or otherwise. Not much in life is perfect, but I don't have any complaints about Sling and I'm still happy that I made the move from satellite. I have all the soccer that I want to watch and a whole lot more for about a third the cost of before. And now that Sling has a DVR function, it's even more convenient to schedule all my footy games and have them ready to view in one place.
I have an advertised download speed of 100, and using various speed tests on a computer, I get some blazing speeds, although on a streaming device the speeds will be a lot slower, of course. But one thing I discovered a while back when my video was becoming 'hazy and out-of-focus' (never went to a black screen, though) for short periods was that I actually was having short hits on the incoming Internet. Thus, the picture would degrade and it would take a bit (usually less than a minute) for it to 'sync up' again. I discovered this by hooking up to monitor the Net on a laptop near the TV, using the same router, of course. Whenever I would have a degraded video, I'd check my laptop and sure enough, there had been a hit (disconnect) on the Net. FYI, this degraded video was not only on Sling, but also on Fubo, Red Bull, and other live streaming apps on Roku. And, it also happens on Fire Stick. The monitor URL I used was shown at this link:
[color=#196ad4]https://www.labnol.org/internet/monitor-internet-connection/27642/[/color]
To sum up, unless there was an ongoing problem with the feed from TNT (and occasionally problems do occur specific to a channel), I'd do some checking on whether or not the incoming Net signal is constant, or having a problem. I would estimate that 98% of the time I have no problems on Sling or other apps, but when it does happen I can trace it to my signal.