Horrible surface quality when printing 2 models vs just one!

[bakhtiaria 0]

This might be common knowledge but I'm pulling out my few remaining hairs.... Single item prints come out pretty flawlessly.

If I try to print 2 of the same item at once, the surface quality goes down the drain.

This happens with all the standard profiles and custom ones too. Doesn't matter which stl.

I've attached sample pics.

The surface quality issues I'm experiencing don't happen when I slice with S3D or PrusaS. Just Cura.

I know that I'm missing a check box somewhere, need help to find it.

 

Thx

Oz