I have the same problem here - also using windows 8. I have not had an update applied on my machine for IE 10 since 3/24 and as with seemingly everyone else here this just started a couple of days ago so I am not thinking it is an update to IE 10 itself that has caused this.
Rather: I saw one of these posts that indicated FTM was somehow using internally a subset copy of IE 10 for this hints syncing. If that is really true then it would appear to me that is where the problem is and FTM/Ancestry developers have to fix it. So I am not going to remove anything right now with IE 10.
I have been able to get around processing hints though, albeit on a bit of a convoluted path;
I have found that if I process all the hints for a person on ancestry (either merge or ignore) and then go to FTM for that person I can get hints cleared up. This problem seems that automatic syncing between FTM and anc.com no longer works. So for now I do all of my hints processing (merge or ignore) on ancestry, then I go to FTM to the person record for the individual I want processed. Hints will still show as unprocessed there with this problem. But if you select hints and then go open any one of the hints and select ignore on that hint from the opened hint and then go right back out of hints to the person record , the hint sync between FTM and anc.com seems to take - or at least it has for me ever since this problem started: FTM shows no hints left after doing this - assuming all hints on anc.com have been processed. A overall sync is required but after everything shows in sync the hints all wind up processed on anc.com and FTM as I had chosen. A bit time consuming if you have a lot of hints, but it does seem to work for now; hopefully someone will get this fixed soon.