player catches on fire when standing on top of soul sand that is adjacent to lava

I was in the nether, mining quartz. while crouching on top of soul sand, I went near some lava which was at the same level as the soul sand. it was quite obvious that I never actually touched the lava, as it was abt ~half level because it was flowing. I must also mention that the lava was below me. I believe that this problem is probably caused by how the game checks if you are in lava.