It isn't just Lemmy.world, and isn't limited to v0.17 either. Lemmy.ca, which has been running v0.18 for days, is also not seeing a lot of federated content, nor accurate community subscription counts from other instances, including lemmy.ml and others running v0.18. I'm posting this from my .world alt because .ca is showing zero comments in this thread.
There have been several not-so-friendly comments made about the issues by someone in [email protected], calling out the site admins of .world and .ml for not sharing their server logs, and the overall silence on the issue. The user's concerns are genuine, but I don't agree with their behaviour.
I suspect the devs were/are completely overwhelmed by the mass influx of redditors these past two weeks. I assume someone is looking into it, but frankly I wouldn't blame anyone if they chose to step away for a few days. I think a lot of folks (particularly "the masses") forget that these are largely volunteer efforts, by people with day jobs.