TL;DR: even if your delete script confirms a full wipe and your Reddit profile page shows zero comment, there may still be comments left over (that you can find through a search engine and delete manually on Reddit).
Weeks ago, I used redact.dev to delete all my Reddit comments (thousands of them over 10+ years). Redact.dev confirmed a full wipe, and my Profile > Comments page on Reddit confirmed I had no comment left.
Yet, as of today, Google still returns dozens of results for “$myredditusername site:reddit.com”. It’s not just Google’s crawler lagging; when I follow those links, those comments are still visible on the Reddit website, under my username, where I have the ability to manually delete them.
Thankfully, I hadn’t yet nuked my account, because I knew of other users whose deleted comments got reinstated (although that was thought to be caused by the deletion script exceeding the API rate limit; supposedly a different case, as those missed comments would still show in the Profile page).
spez: edited for clarity.
I saw your clarification that the comments persited on reddit.com. My thought was maybe the part of the DB which manages the comments of the posts was lacking behind.
But after weeks this should not be the case, so I take my comment back.