Coming up on 5 years as an Imgflip user, 3 years as a Community Moderator.
Not sure if you remember, in the old days, an approved submission could go back to submitted status with just a few downvotes. A lot of users had "followers" that would abuse that algorithm.
The dark days of downvoted to submitted ended July 2018, imo one of the best site changes ever.
Sometimes the site will change a lot of things in over a month or two, October 2018 was one of those time periods. Other times it's incremental, to change one or a few things in the Image Generators. Sometimes it's a change that's barely noticeable, under the hood so to speak.