well it happened with a project that uses no external footage whatsoever… As said earlier, I could live with slower ram previews… the global cache compensates for that more or less. The problem comes when the cache itself stops caching. Then I lose the point of it all and switch back to 5.5. No global cache there, fine. It works as expected. I do my best to understand the software beyond the buttons in the interface but when it comes to some random interpretations of issues and me trying to fix it on my own (because there is no clear answer to what cause it, I checked), I’d rather just stop. It should not be that had. I’m a little irritated, I admit.
Sounds a bit like a bug. But it might also be that the compositing of the layers is such a “cheap” processor operation that it’s being done live, while the layers themselves are being cached. It maybe that this is quicker than reading uncompressed cached frames from disk. What kind of disk is your cache disk? SSD?
When it fails to cache, are you then finding that a subsequent RAM preview is taking lots of time to recalculate the frames… or are they there just about immediately? In other words, is it about the indicators or about the performance mainly? I’m still wondering if the issue with it not working like you expect is to do with a problem or with your expectation. Are you expecting to always see a blue line?
I’m not saying that it’s not a bug or that Ae is perfect, but I know when I started using CS6, I had lots of similar issues with global performance cache, and how it was visualised that turned out not to be issues. At fault was my expectation of how it should be visualised.
Seriously though, if you think it’s a bug, file the bug with Adobe and it will be looked at.