Increased video noise in 720p exported videos after update

I'm just wondering if anyone else has noticed that there is a lot more grain in the 720p h.264 videos that are exported from Final Cut after the major update to 10.3. I shoot most of my videos in 1080p and then export both a 1080p and 720p quicktime version. The 1080p version still looks fine but there is a significant increase in the amount of grain in the 720p version now. I'm wondering if any export settings were changed in the update?

I still use this when I export:

Format: Computer
Video Codec: h.264 better quality
Resolutio: 1280x720
Color Space: Standard - Rec. 709 (this can't be changed).

Anyone seeing this same thing?

Do this daily, not seeing anything. How hard are you pushing color correction or effects that effect luminance?

I'm actually not doing any correcting to a lot of the clips that I am seeing noise in. The raw clips don't have the noise and the 1080p exported files don't have noise. It's only when I export the 720p versions that I'm now seeing significant noise so I figure it must have something to do with the export settings. But this wasn't happening before the 10.3 upgrade. It's weird...

There are several threads about this e.g.
www.fcp.co/forum/4-final-cut-pro-x-fcpx/...-if-not-fullhd#82907

Yep, it looks like it's happening to a lot of other people too. It must be a codec issue. Hopefully, apple comes out with an update to fix this issue soon!