Comsol With matlab: non monotonous interpolation grid

Hello all,

Im using Comsol 4.3 with matlab.
I use the transient time solver.
Anytime I set the solver for short time stepping < 1e-4 seconds the calculation crashes and I get the following error:
" Non-monotonous grid interpolation"
this is used for transient time <0.8e-3 s.

If I change the transient time to > 1.2e-3 s, no errors at all.

Would you please explain to me this problem

Thanks
Mounir