Always glad to help where I can, and sorry about the confusion (of duplicating the color-bars limits for the broader capture limits). Which stirred me to thinking ...
The color-bars are a good relative guide but perhaps not representative of the included content. I mean, often I check and constantly see "professional" DVDs & Blu-rays crushing and blowing-out their spectrum limits. (That doesn't include Lucas or Jackson, BTW; they're allowed with their "license to kill" colors [cue 007 theme].)
Do you check that you never actually hit 0 or 255 during the entire stretch of the capture? Not that it's "illegal" to do just that. But we'd never know if such pixels were at 0 or 255 or actually beyond those limits.
Therefore, should your working safe-area be 1 thru 254, at minimum?