Lava remnants not dissipating after removing source block

I was attempting to build a tower-like structure on which I intended to place source lava blocks at the top in such a manner that the lava would spread down the tower's sides. However, no matter what situation I try, when I remove the source lava block, the lava always stops dissipating at some point (usually on the floor) and I am left with lava which never disappears completely. I have attached my save folder for the world I was working on and left a sign with instructions.

Other thoughts: Behavior of fluids has been very frustrating to all Minecraft players for a long time now and it would be great to see an improvement on it soon.