https://x.com/ChujieZheng/status/2039909917323383036 is the pre-release poll they did. ~397B was not a listed choice and plenty of people took it as a signal that it might not be up for release.

A Qwen research member had a poll on X asking what Qwen 3.6 sizes people wanted to see:

https://x.com/ChujieZheng/status/2039909917323383036

Likely to drive engagement, but the poll excluded the large model size.