Marcin Momot does say the development team is looking into it for a future patch.
We know that The Witcher 3 is getting patch 1.08 fairly soon. We also know that this patch is geared towards fixing quite a bit of the things that have made playing the game frustrating to some, despite the fact that on its whole it is one of if not the best game released so far this year. All of that is the good news. The bad news is that CD Projeckt RED has confirmed that the patch will not be able to retroactively fix any achievements players might have earned but not received.
On the flipside, there are going to be some achievement issues fixed, which means that those that have tried to clear certain achievements but haven’t actually cleared them such as finding all Gwent cards will now actually be able to gain achievements. Marcin Momot took to Twitter to deliver the bad news but did add that the development team is looking into a fix. What he did say is that patch 1.08 will not be able to award achievements retroactively.
Momot added that they are looking into the situation, which could mean that a later patch might be able to do what this one can’t. He also said he couldn’t make any promises on whether the team would ever really be able to add retroactivity when it came to patches. Of course, before we can start looking at and hoping that a future patch will bring retroactivity to the achievements, we need to get the upcoming 1.08 first. CD Projekt RED still isn’t shedding light on just when The Witcher 3: Wild Hunt will get this patch though it’s expected sooner rather than later.