This popup was recently introduced in PR-2174.
I don’t know exactly why, but voyager prompting me that I’m about to lose my progress was sort of strange to me in the context of scrolling on lemmy.
I understand why someone wants such a feature, but IMO this should be turned off by default and available as an option.
People have been pointing out a common issue with accidentally going back for years. I think this is a simple to implement way to address the issue.