I'm not sure about the titanium but maybe titatium is pulling the sing. titanium lookes at the sing in its topleft and moves it down towards the TTAN. (I honesty don't know at this point).
with the, moving down with air preasure off: sing must be moving with the low preasure it makes. This is why sing tends to clump together.
I think I know why all these thinks happen. It goes to to top left because of subframe mechanics. Basicly The sing looks at its topleft neighbour first and then moves that way.
its similar if you give a scripted liquid gravity, except it goes in the opposite direction, i think it IS infact just a small number, bc TPT has both -0.00 and +0.00
Use Quartz! It makes a Wave!
It could be that -0 is actually just a really small number, like -0.00000001. Or even just -0.01.
the negative pressure goes where there's no material blocking
Not only that, but also other materials have a tendency to go upper left. Playing with flamethrowers, I always saw a slight bend to the upper left.