I can confirm as a runner that sweat can do that. I don't have YouTube premium so I listen with the video open. When I use a fanny pack on my back, I can sweat enough through it to trigger the screen if I don't face it away from my body. It also happens if I have my phone in the back pocket of my jeans walking around on a hot day.
I had an episode so bad last month, I thought I had somehow gotten a virus. My screen had a full on seizure and I shut it off. It was close to 100 degrees and I had just ended a phonecall. It looked like my phone had been crying.
damn
when i saw the cum in the phone i was like no way the cum gonna answer the phone and it did BRO JKLDFKSDJFKSJFKJDKJDKF