The bug
When using a fire charge on a non-flammable block, it attempts to make fire on that block despite when using flint and steel it doesn't work.
Affected Blocks
Rails
Saplings
Pressure Plate
Brown + Red Mushroom
Warped + Crimson Fungus
Glass Pane (Including Stained)
Iron Bars
Sea Pickle
Crimson + Warped Roots
Nether Sprouts
Weeping + Twisting Vines
End Rod
Torch + Soul Fire Torch
Cactus
Ladder
Redstone Dust
Tripwire Hook
Snow
Dead Coral
Dead Coral Fan
Chorus Plant
End Portal Frame
Lilly Pad
Heads
Grass Path
Farmland
Fire + Soul Fire
Affected Blocks while crouching
Chest
Daylight Detector
Buttons
Grindstone
Enchantment Table
Stonecutter
Since you can actually place fire on soul sand in 20w11a, you need to reproduce this with other blocks (such as rails) instead.