Not sure how long it's been like this but the lava levels are set wrong. I think since the build levels are increasing the lava say is down at level 38 but it's actually higher it just shows it's down at level 38. I recreated it with a spawner in the nether. In the video you can see the piglins are catching on fire before hitting the lava. Not sure exactly what levels the lava really is set to and what level it's shows the lava is at. It's not my texture pack cuz I took it off and it still happens. https://youtu.be/hkx15CbtZos