I too have tried to feather edge a SLU, but I fiind I have to hit it at just the right time or it is a lot of work. My preference is to let the SLU dry and feather the needed area with something like Ardex SD-F.
Works for me.
Yea minimal prep covers a few saw cuts and doorways.
The installer packed feather into the cold joint? Didn't you alert the GC? That will just be a call back no?
Offer.... I never offer to give money back. But the GC takes it.
Cold joint when pouring SLU= where the SLU sets to the point it is not workable and another pour to it results in a joint.