Error using deval ... Attempting to evaluate the solution outside the interval ... where it is defined.

Dear community,

I am using the PDE toolbox for thermal modelling. My model is composed by seven calls to the function developing the thermal model and should run for a number of cycles. When I run it for the first time I get good results, but when it enters the second loop, it solves the first call to the function, but at the second call, it prompts this error:

"Error using deval (line 132)

Attempting to evaluate the solution outside the interval [2.136200e+00, 2.136201e+00] where it is defined."

The tlist in the thermal model is defined as tlist=linspace(t0,t0+duration,nsteps); where nsteps is the duration divided by the time step.

t0 is 2.1362

duration is 0.0444

time step is 1e-4

Could you please help me sort this out?

Many thanks,

Giulia