In opening 3 projects, I've found quite a few bugs. In one, an image mask effect I had applied, but turned off was turned on.
In another, I used the tint filter to tint a background orange. I had also tried a color correction on the same clip, but turned off the correction. The correction was turned back on, the tint filter was turned off, and the tint filter was reset to blue, not orange.
As well, it seems all my projects are completely unrendered, except for clips that only have color correction applied and were rendered. All dissolves, texts, everything else has lost it's renders. Not the end of the world, but annoying.
I also had many instances of RT Drop shadow placed on my clip in the primary, as I was animating the crop, with a background under the primary and wanted a drop shadow. FCP X completely removed all instances of RT Drop shadow on the primary.