We’re literally talking about the same thing, but ascribing different motivations.

I do think the test a new model and realize their index is broken- the new model isn’t on top, so they change the weights to make sure it’s on top.

The difference is that you seem to think they are doing so out of some innocent feeling that the new model is actually better, while I think they are doing so because they were paid to do so. I think my interpretation is more likely, but that’s just me.