[FLUENT]Marangoni effect

Hello, I've built 2D model of laser spot welding in Ansys Fluent.
Recently I wanted to add Marangoni BC so I've enable "Marangoni Stress"
in "momentum" tab and enter 0.00029 [N/m*K] (for 304 stainless steel).
Tried also other values for different sulfur contents. Values of surface
tension gradient was taken from "Surface tension of molten stainless steels under plasma conditions" T. MATSUMOTO, T. MISONO, H. FUJII, K. NOGI as derivative dy/dt of y= 0.29×T+1030(y - gamma ;-) ).
My problem is that liquid zone is enormous compared to case without Marangoni BC.
In attachment I put a picture of the case with one laser pulse (timp =
30ms, Pimp = 1315W, radius = 0.350e-3 m, tophat) without the Marangoni
effect and three cases with different values ​​of gamma. Both cases
differs only in the inclusion of that effect.
Have any of you met with such a problem or have an idea what could be causing this?
P.S
cases are axisymmetric with symmetry to the x axi so there is only one half on the pictures.