Thanks Stan. I'm using 6.0.1.013. Haven't seen an update in Creative Cloud yet.
I went ahead ignored the error, built an ISO using Encore, then burned and verified it using Toast. The ISO is only 24.17GB.
But the disc won't play on my Samsung BD-C5500. I know that player supports BD-R discs, but I'm not sure what the problem could be. Encore's "check project" panel shows 2 additional warnings, but I don't think they matter. "End action won't execute because of end action on the final chapter point". I'm aware of that, and the only option is to delete the end action. Either way, shouldn't matter, right?
Is there any software that can check a BD disc structure for problems, so I'll know whether to blame Adobe or Samsung? The disc plays fine in "Mac Bluray Player" and VLC.