Primed TNT isn't treated as an entity.

I was playing in a superflat world and and decided to play around with TNT cannons. I built a TNT cannon correctly but the projectile TNT didn't fly off. I was a bit confused to why it did not fire. I tested by making a clump of TNT and lit from the top, only for the TNT to drop like gravel or sand and the explosions would not make the TNT fly off like it normally. I'm not sure weather a this issue was a bug or if it wasn't a feature in the bedrock edition of Minecraft.