I would be charitable if I said I believed it was a pure error. The buildings in Kiev that got targetted, apparently not too far away from some actual war-related place (chemical plant? - not that the actual striking of one of those is going to be too brilliant[1]) and the shopping mall that is much further away from the front-lines could be similarly not too much more distant from something 'legitimate' - with heavy-duty use of quotes there in a generally illegitimately created conflict - that should have been the recipient of the strike.
Or Russia just did as the US did in Yugoslavia (and in countless other cases) and precisely hit an imprecisely identified target (this time it wasn't a Chinese Embassy/whatever, though).
But these are just excuses. Every possible interpretation puts Russia (and/or those directly responsible within Russia) in a bad light, just various different hues of that light. Incompetance, carelessness, psychpathy, etc... If they choose to say anything about it (internally or externally), they will of course choose whichever version they can best spin. "There were International Mercenaries training there, in secret" or "Ukraine got a lucky interception onto our missile, which then fell onto their own mall" or something. So far, I've not heard of anything they said, so maybe it'll just be silence (publically, at least).
[1] We've seen what happens with actual chemical-plant incidents, and yesterday there was that single shipping-container of Chlorine apparently dropped in that Jordanian port..