Surface hoar too large

After checking my slope simulations, I realized that a surface hoar layer is too large on the south facing slope, when I run it with coupled_phase_changes = TRUE. On 6. Jan 2021, the grain size of this SH layer increased from 0.8mm to 130mm within 3H. If coupled_phase_changes = FALSE, no SH layer will be buried. I attached ini and smet file (here it's set to false).

VDLS_met_2021_cleaned.smet

VDSL.sno

VDSL1.sno

VDSL2.sno

VDSL3.sno

VDSL4.sno

VDSL5.sno

VDSL6.sno

VDSL7.sno

VDSL8.sno

io_tmp2021.ini