Exactly - it can be avoided, as graphs by Miska showed with the same DAC.This was what I said. It doesn't matter in real life. But since it can clearly be avoided, there is simply no good reason not to.
[Edit] Did you notice any problem with your RME DAC before you see those graphs? If not, what is there to worry about?
Who said I am worried about anything? You are the one that hinted it was poor DAC design not me?
I simply pointed to measurements Miska showed in this thread, that make the ultrasonic plots look nicer. Nothing more than that.
If you think the RME should do a better job in ultrasonics without PC software upsampling, then you should mention it to @MC_RME