That sounds odd.
What exact version of AE are you using (down to the last decimal)?
Also, version of OS and other system specs wouldn't hurt.
Is everything shape layers, solids, and adjustment layers or are the Illustrator files, PSD's, video files, etc.?
AE 18.104.22.168 on Windows 7.
There are AI files, pngs and jpegs as well as solids etc. Only plugin I'm using is VCP Reflect on a few of the images. This really seems to have something to do - suddenly - with this masked adjustment layer with a blur. Don't know why because I already have several in this comp and it's only now an issue - and I mean the exact same thing, I duplicated the "problem" layers from layers that are fine. I even tried doing a full render of the problem section and it failed - no explanation.
It apparently did have something to do with the VC Reflect plugin as I was using it. I went through and removed every instance of it and now it's at least rendering.
Video Copilot's effects are usually well-behaved and useful, but every once in a while they seem to get a bug up their butts and they go a little bit crazy. Not the kind the murders you with the candlestick in the conservatory, but more like the kind that leaves its shoes on the floor just in the walkway enough to trip you, but pretends that it tried to put them where they belong.
Yeah, and I've noticed Andrew Kramer frequently warns people off the collapse transformations switch as it can cause unforeseen issues...I think in this case using that in tandem with VC Reflect made AE freak out. I was only really nesting for organizational purposes; maybe when I get everything laid out and timed I'll just move all the layers back into the main comp and try to reapply it without any precomps or collapse. It did add a nice finish to some parts of my video. Thanks for your help; I'm still not exactly sure what the problem was, but it def appears to be VC Reflect-related.