Galaxy S8/S8+ owners that have already got their hands on Oreo will be receiving new ~530MB hotfix builds that will likely prevent their phones from facing the same issues. The two builds are G950FXXU1CRB7 for the S8 and G955XXU1CRB7 for the S8+.
Meanwhile, Galaxy S8/S8+ users still on Nougat should expect much larger builds that will certainly include the same hotfixes their Oreo brethren are receiving as well. At the moment, we have no build numbers for the new complete Oreo builds.
Have in mind that the update has been initially spotted in Germany and it might not show up for you just yet provided that you're in another region. It shouldn't take long, though.