I normally agree with this, but they objectively did lower the default effort level, and this caused people to get worse performance unexpectedly.

And it does seem likely to me that there were intermittent bugs in adaptive reasoning, based on posts here by Boris.

So all told, in this case it seems correct to say that Opus has been very flaky in its reasoning performance.

I think both of these changes were good faith and in isolation reasonable, ie most users don’t need high effort reasoning. But for the users that do need high effort, they really notice the difference.