There have been problems like this in every election with these machines.
More troubling, exit polls and voting results have routinely disagreed with each other since 2000. In most countries that would be taken as proof that the election was not fair. But not in the USA!
http://www.ukprogressive.co.uk/breaking-retired-nsa-analyst-... claims evidence of systemic manipulation of the vote, with the trend strongly being in the GOP's favor. I have not personally verified, but it would not surprise me.
Anyone who has been paying attention this election cycle knows about the attempts by both sides to manipulate rules about who can vote, when, in ways that advantage themselves and disadvantage each other. That happens in a lot of elections but not to the extent of this one. With weird results such as, because of a recent law in Ohio, polling workers have to ASK for ID, but due to a court decision, they can't stop you from voting if you DON'T have that ID. (Confused polling workers are sure to get this wrong.)
The general trend is that Republicans want as many barriers to voting in person as possible, while Democrats want as many to be able to vote as possible. That is because more marginal voters are much more likely to be Democrat than the general population. The stated reason is "to prevent fraud" even though there is very little evidence of such fraud in practice. On mail-in ballots this reverses, since the GOP expects a large portion of mail-in ballots to be from military people who are likely to vote Republican. Fraud has been more of an issue with mail-in ballots, but obviously people are not as worried about that.
Laws get broken as well. For instance the 2000 election was decided in Florida, in part due to a voter purge that the courts decided was illegal. See http://en.wikipedia.org/wiki/Florida_Central_Voter_File for verification of that. The lesson learned is that voter purges work, which is why Florida was trying to do a purge this year at the last minute despite being warned that it was illegal. Because flipping the choice for President was easily worth the slap on the wrist they got afterwards.
There already have been laws broken this year (see http://www.cbsnews.com/8301-250_162-57535950/man-charged-aft... and http://www.tampabay.com/news/politics/national/fbi-launches-... for example), and everyone expects the lawyers to be gainfully employed as a result.
In short, get out your popcorn. When we exercise our right to vote, the vested interests exercise what they see as their right to manipulate the vote, and this time there is a decent chance of fireworks.