How do Precipitation Reactions behave in the Absence of Gravity?
In gravityless environment, all directions are equivalent save the very vicinity of the surface(*), where just few water molecules are toward the surface.

Therefore, in the bulk volume, the precipitate would stay where it is, unless some currents exist for whatever  reason.

At the very surface, it depends on nature of precipitate.

If it is rather hydrophilic, water molecules would have tendency to surround it, so it would be rather pulled from surface inwards.

If it is rather hydrophobic, water molecules would have tendency to expelled it, so it would be rather pushed outwards to the surface.

If it is far enough ( tens molecules ) from surface, all effects will get spherically symmetric, but one....

(*)  .....  as in a very very long term, precipitate denser than water would be more concentrated near the centre by the own gravity of the "bubble" and vice versa.

I am not aware of such an ISS experiment, but it makes little sense to do it for me. In the microgravity context, it is very very long term experiment.