This is likely a server distribution issue, not an intentional act on Reddit’s side.

Basically, big websites need a way to scale up to a huge number of users. A single server would quickly light on fire if it’s handling all of the API requests from every single user. Every single home feed refresh, comment, post, etc… So instead, you have a bunch of smaller servers, which all get the same info from a master server. Like satellites orbiting a central hub.

The master server is able to keep up, because it’s only handling the update requests from the satellite servers. This master server basically holds all the “info” about the site, and all the smaller servers push/pull updates from it. The master server never has to deal with all of the small “user wants to refresh their feed” types of requests, because the satellite server already has a local copy of the info. No single satellite server gets bogged down by users, because there are hundreds (or even thousands) of them, and the central server is only having to deal with the updates.

Another way to think about it is like a tech support company. You call in and talk to a tech support representative. You don’t talk to the CEO for minor tech support questions, because they’re only one person and can’t field every single call. So there is a small army of tech support roles, who deal with the small day-to-day stuff, then the boss deals with bigger things like policy changes.

But they’re likely going to prioritize recent content, because users want to be able to interact in near real time. So any older content updates (like edits or deleting old comments) will likely be queued behind all of the more immediate stuff like new comments and posts.

So let’s say you make a comment. Your request goes to one of the satellite servers. That server takes your request, processes it, and sends it off to the master server. The master server queues that update to get added based on priority, then all the other satellite servers pull that update from the master.

So on your end, you made a comment, saw that it was processed by the satellite server immediately, and your comment appeared. Yay! But someone who is across the country may not see your specific comment immediately, because they’re on a different satellite server which hasn’t received that update yet. It may take a few minutes to get distributed over to the other satellite servers. And this delay is compounded if things are being pushed back in the queue due to being a lower priority.

So how would this cause comments to get undeleted? When you’re editing then deleting 2000 posts, that’s (at minimum) 4000 updates that you’re sending to your satellite server. So if you come back to it a day later and happen to connect to a different satellite server, it may not have received all of those updates yet because they’re still queued.

Yes, it’s possible that Reddit is somehow automatically detecting things like PowerDeleteSuite and somehow restoring the edited/deleted comments from a backup. But the much more likely scenario is that your edits/deletes never actually made their way to the satellite servers due to being low priority, or got lost in the queue and timed out.