I am on a brand new iMac but my old iMac was doing the same thing. We've already established that it has nothing to do with what machine you're on or what type of footage you're working with.
We have established already that the command "sudo purge" in terminal fixes the issue for a while but then it comes back again. We have indeed been able to isolate the problem right down to a very specific folder - the cache files - and determine that it has something to do with Premiere Pro filling up that folder like crazy. That's very kind of you to be willing to work with us to fix this. Yes I've filed a bug report but I'm losing all confidence in Adobe's engineers' ability to do anything about it. But if I have to sit here for 20 seconds everytime I move my mouse, waiting for the clips in my sequence to quit flashing on and off, I will have to think hard about canceling CC and return to FCPX. I missed tracks and FCP's filing system was a joke to me.
I'd finally given up on FCPX last year and moved over to Premiere. In all that time some low-level engineer couldn't be sat down with an iMac and a few GBs of video footage and told to edit a video? I think every poster here is confident the problem would soon be replicated. In combing through the internet searching for a solution, I am seeing complaints on various message boards from at least three years ago from folks using v.CS6.5 and who knows which OS. While I'm "happy" to see I'm not the only one suffering from this annoying, time-wasting bug, I'm dismayed by your repeated claim that your engineers are unable to replicate it (and subsequently fix it?).