Solidus Temperature and Solidification

A hot liquid droplet is exposed to a colder gaseous surrounding. Solidification/Melting is activated to simulate the solidification of the liquid droplet. Although the temperature has fallen below the defined Solidus Temperature in parts of the liquid region for some time steps, these parts are still not solidified. What could be a reason for this behavior?

In the material panel of the liquid which is expected to melt or to solidify it is not only important to set the Solidus and Liquidus Temperature properly, but also the Pure Solvent Melting Heat. The default for this is zero and has to be modified to allow the phase change.