solid infill first layer seams

Hi,

Well I've been thinking about this one for some time. The image below shows the issue-



I did observe the movement algorithm and I understand why it happens. The printhead moves continuously in one direction leaving gaps on the way, and then comes back later to fill them. It is important because it is optimal movement pattern
But, when it comes back to fill the gaps, then there are seams clearly visible. It is probably because the new plastic extrusion is different in temperature to the connecting one.
It would be nice to hear some ideas on this issue

thanks