Parallel vs Serial post-procesing

Dear support

I am trying to generate animations in Paraview but I am facing problem when using parallel post-procesing. I have attached an image where you can observe the Q-crit obtained by using multiple CPUs (top image) and using a single CPU (bottom figure). The lines in Q-crit contour are the limits of the domain blocks coming from the CFD solver which imports an extra cell and this modifies the spatial gradients in the domain. It seems that for a single CPU it is handled in a better manner than when using multiple CPUs.

About the workflow, I imported the data (made by multiple blocks), I used the merge filter and then I did the rest of operations from the merge filter.

Is there any way to improve the parallel calculation of Q-criterion and avoid having these lines at the block boundaries?

Thank you in advance!

Could be the problem solved if a GPU is used instead of multiple CPUs?