Hi, that happens to me too from time to time and not only in a7 but even some 2 months ago using then dated dailies and so on, in my case this strange behavior is cured by restarting max and reloading the scene, yet I don't think that's some memory insufficiency related problem as it does happen even in scenes crunching no more than something around 15gb of ram of which I got 64gb. Still it does happen, even if very rarely and in most cases when I do a lot of test renders without restarting max, which I think is not too clever to do when using corona, vray or any other renderer :) - actually if I think about it, it is no more frequent than 1 time a week given 10-14 (or more sometimes) hours of work per day so I didn't report it as a bug cause I thought that's just my pc misbehaves, given the windows is more than two years old without reinstalling it and is probably infested by some cleverly hidden viruses, tojans and other "pleasant" little things which come with the windows living for so long :)
