Dave - Agreed, I am very much used to Class 3 PCBs, so I immediately notice when etchback is not present. I did look at the image in more depth after my initial email and noticed that there is a straight wall with evidence of voiding and irregular plating behind the wall. So it looks like the desmear step was poor at best. Normally I would send this to ST&S (Gerard O'Brien) for a professional look (I know PCBs well enough to be dangerous but not always correct).
The desmear doesn't look very good. This may be a point of contention, but is the first concern,
The second concern is as you stated, is etchback required, if so, then this is hard failure mode.