when I was crossing lava with warped planks, the planks lit on fire, they are from the nether, they are not sopost to go on fire, then I died to What I think is a bug. sadly, I have no idea how to place screen shots from a switch but to recurate glitch try , 

flowing or source block of lava

crimson or warped planks placed next to or in lava pool

The reason I say this is a glitch is because I bridged with spruce planks 1 block above lava and still the planks did not light.