Deleting posts and comments

A few days ago I finally found inspiration to go back and delete all my content from reddit — 15 years' worth.

I wrote a little script using PRAW to first go through posts then comments, fetching 1,000 at a time (the most the API supports per query) from each category and time frame, then deleting them. This appeared to work perfectly — I now have no comments or posts available when I log in and look at my profile, and my script no longer finds any via the API.

Then yesterday I got notified of a reply to one of my old comments. Clicking through, there was a comment I'd made a year ago, still intact. I confirmed it wasn't visible through my profile then deleted it, but now I'm worried that much of my content might still be available without being visible in my profile.

Is there something I'm missing? I recall hearing during the API changes that some protections were being put in place to prevent users from deleting their content — have I bumped up against that? Should I just delete my account and forget about it? Would a GDPR request to delete all my data work?

Any insight as to what's going on here would be much appreciated.