Why don't YouTube links work in comments?
In order to prevent spam, YouTube has disabled the ability to comment on videos with links. This means that you can't include a link in your comment when you post it. If you want to share a link, you can do so in the description of the video. Apr 12, 2021
Interesting, I put the download links in comments on my videos on my channel, and they stay up fine. In that case then, maybe it's auto deleting comments with links on other peoples videos/channels and not on your own stuff (?).