NU_refinement give stretched map

Hi ,
I am using NU_refine to refine my structure. However, the output map is stretched along one direction. In the mean time, The result from Homogeneous refinement does not look the much stretched. Wonder what should I do to resolve this issue? Thanks

Here is the view distribution

First thing, try setting the FSC threshold to 0.75 in NU refine.

Thanks for you advise. I tried set it to 0.75. it did not help.
Also, I noticed that this stretch effect only start to appear in the last two iteration( like 8 and final here, iteration 7 is fine.) Seems that right before it start to output map_filtered.
Do you have any advise on it? Thank you

How does the raw map look? I guess your orientation bias is leading to oversharpening in a certain direction.

What if you do a local refinement, with the resolution limit a little bit more conservative? Like 4-6A.