Strange filling-up behaviour of fluid

[Thomas Engelhardt]

Hi All,

I'm struggeling to fill up a cup with liquid accordingly to reality. Under the following Links are a screencapture an a screenshot.
Basicly everything works, but as the fluid pours into the cup, it fills only on the inner surface of the cup until the fluid reaches the top of the cup. Once at the top the fluid collapses into the cup and the rest of the volume is filled.

Bildschirmfoto 2024-03-19 um 14.56.57.png

Why is there no even distribution of the fluid (water).

Thanks in advance and sunny regards, Tom

Link to video: https://www.dropbox.com/scl/fi/j0iv72eo ... ng_cup.mov