Distance errors for constraints in large terainn reconstruction

The images were taken on 2 days, under similar lighting conditions.

Every day aligns on its own perfectly with no distorsion.

800 on 1 day and 800 photos on the other day

if I add pics from the second day to the aligned project the error for all distance constraints will go from 3cm to 30cm.

I admit that I have not tried to add the second day in batches, of like 200 or so pictures , would that make a diffrence?