Does anyone know if this issue is being investigated? I understand you must play the whole game without save and loading to get some achievements, but that might take a while and for some reason, super easy mode on blitz I cannot win lol. I won on nation by far, but this is too difficult 

The 12/18 star achievements have been fixed in the latest patches. The wonder achievement is still bugged. Don't know of other ones.

The Wonderful scrollbar on my achievement list has always been stuck at 0 with a bizarre divisor -- currently the text is "0/4,194,303":

<div class="progressText nextToBar ellipsis">

                                        0 / 4,194,303                                                                            </div>

Well... there's no point in fixing the typography which causes the divisor to appear as though I'm in a German locale ("0 / 4.194.303") because AFAIK there aren't more than 999 wonders in Humankind! I think there are only 22... so there must be a bitmap with 22 positions somewhere... and maybe the monstrously-large divisor is the result of interpreting the bitmask 0x3FFFFFF as a binary integer rather than as a unary integer??   

At a guess: the QA team on Humankind must have assigned a low priority to this defect because it'd be an easy testcase to construct, and an easy defect to repair.   But then again... that's just a guess... and if the bitset process hasn't been working properly whenever a wonder is created, repairing this display-defect won't magically reconstruct the player's progress to date, then I should hope it'd be a higher priority to track the players progress accurately than to report it...

The good news is that the 12-star and 18-star achievements have all worked fine for me over the past few months, so there's at least some forward-progress being made on defect repairs for player-progress.