I found one instance of a rare pet prefix not getting the proper weight modifier on accessories, which will be fixed.
Besides that, the weighted drops are consistent across affix groups. It’s about 10x the normal probability of getting a weighed affix relative to everything else, so I feel like there’s some skewed expectations. There’s nothing that says, for example, that Bargoll’s Core won’t roll acid modifiers on it. It is however 10x more likely to get a pet affix than those acid affixes when it’s rolling in that affix pool.
I’m not sure what exchange you are referencing, but it must have left quite the impression.