OK, and the flow field at that point? The table shows it's gone wrong, I'm hoping the contours in the few time steps leading up to that will show why.
Density for the particle falling is relative - ie it's based on the density difference with the carrier fluid. If the problem is linked to precision then 1g particle in 2500kg/m3 liquid (same density difference) may avoid the issue.
You are navigating away from the AIS Discovery experience