Hmm, I didn’t see anything about setting up the zebras there.
The issue with zebras is that they’re derived from the JPEG settings of the camera - so having them set improperly can result in the camera underexposed significantly compared to what would put the highlights just under the RAW saturation threshold.
There’s a bit of discussion of zebras settings at Sony A7R3 zebras are truly RAW: Sony Alpha Full Frame E-mount Talk Forum: Digital Photography Review - apparently, with the standard picture profile, you won’t clip the raw sensor data even with the zebras set to 105% or more.
I had missed the interesting observation that zebras are only calculated from the green channel before - that explains why I’ve so frequently had issues with blue/red LED lighting looking horrible despite no apparent zebras!