Half of the picture - that's because on Rift the UI is not readable when scaled down because of the low resolution, so there it is kept in original resolution and you have to move your head to see it all. The riftless stereoscopic mode shouldn't be doing this, but I basically only put it there at the latest moment, and I didn't catch these issues.
The second issue - with low fov the quality metrics causes generation of many tiles, and even though the tile cache size is adjusted for it, it's not adjusted enough, apparently. We'll probably have to handle lov fov differently, caching a wider area and lowering the metrics. For now, try to lower the terrain quality setting with low fov.
