I recorded a few videos recently. Like with every video I capture after learning about the feature, I set videoBitrate to a higher value than its default of 5Mbps (80 in this case) in order to avoid blocking artifacts. Unlike those other videos, these last few don't keep the bitrate constant to the set value, whereas it did before. Furthermore, it behaves almost exactly as if it were using constant rate factor mode instead of constant bitrate. Has the behavior been changed? I'm enrolled in the public test channel.
S7 Exynos Nougat. 2017 Gear VR. Public test channel.