Some times it is also good to differentiate what we like and then what are specifications and then what all can meet specifications. (bolded and underlined for clarify confusions what I mean and for give some direction how to read next things.)
If look tightly specifications as they are even these individual manufacturing lots what have this "we do not like this - issue" they do not violate specifications if we look specifications tightly as they are. Of course if we look 1kHz good shape square wave and how scopes typically show it and what kind of display is "default in mind". But, if we draw all worst cases what still do not violate specifications we can surprice.
Here is some kind of draw about level specifications.
Red marked area is accepted error area aka error window. Green line (3 div up from center) is this imaghe reference level "0 dB")
I have not draw these worst case square wave shapes what still meet specs. But everyone can imagine it quite easy as long as he remember what is square wave or what ever other wave than pure sine wave. In mind try dfraw worst case square where what ever harmonic sinewave is affected how ever but inside specification max errors.
Who want - home exercise: draw worst case square wave shape what meet specification. Use example 1 or 10k square and up to 11th or even 13th harmonics (also use right level of harmonics and then every harmonic affected maximal level errors.. note also that level errors are not specified so that freq rtesponse is continuously and nicely only decaying over freq range. (remember kleep enough rest breaks and also some fun)
Of course it is not at all what we like and what is our expected square shape in mind based some experience and simplest school books.
Who can accept 1kHz square wave what is worst case and still inside specifications. I do not like and I believe most do not like but claiming they are out of specs is just misunderstanding. Of course, I can always say I do not like this and that - I do not accept this and that.
But I can not claim there is violation of the limits of the specifications. Who is
responsible (in law) if some people do not like or accept some things
with his own standards in mind what he individual people accept or not, like or not like.
Add: It looks like some peoples can not read so I want pop up this to these eyes who read unconcentrated.For build better reputation or keep even allready earned reputation I think it is still wise Siglent handle this case very differently and do all for every customer who do not like this feature and can not accept it. Even if they can still win in law room do they violate or not promised specification. (yes they win if some want try).
Back to right road. Add: <<== (and for avoid more misunderstoodings: this was for Siglent as connected to just previous two sentences)