Yes. I don't get this. If the 512 bits that are generated every minute are publicly known then they certainly aren't useful for any function where the seed is meant to be some sort of secret.
If someone know that you are using only this, they can try to guess when you get your numbers and use brute force with all the options. For example if they know the day, they must only try the 1440 possible minutes.
Something similar was used in the early days of HN: "How I Hacked Hacker News (with arc security advisory)" https://news.ycombinator.com/item?id=639976 (928 points, 2968 days ago, 79 comments) [note that HN was much smaller these days, 928 points was a LOT of points]
