Due to the filler addition, typically your Linear Viscoelastic Limit (LVE) will reduce, and there could be two possibilities why your results look like this.

1) Due to the lower LVE limit, you are already reaching the Non linear limit. As the temperature decreases, then also your LVE limit will reduce. Therefore, if you see the 25°C curve, the curve starts to flatten out earlier (around 12%) but for 30°C it is closer to 17% or so.

2) The second possibility is that you have already reached the limit of your device. It cannot apply anymore torque because the upper limit is reached and your mastic is too stiff. You should check the status of the measurements if that is possible with this rheometer software.

Mrinali Rochlani Sorry, PhD, I want to ask what this sentence means

You should check the status of the measurements if that is possible with this rheometer software.

Usually there is a column in your results table in the software of the rheometer that indicates the status of the measurements, like if the torque is out of the range or the strain was not reached or some other error.