I recently posted a link on Reddit pointing back to a guide that had been created on one of the communities here.

Originally I used a PieFed link, but I had to quickly update it with a Lemmy link instead because anyone attempting to use the PieFed link was immediately greeted with a login page instead of the guide.

I tested this again today, but it looks like PieFed is no longer forcing the login page when viewing this post while logged out.

Is this something that happens occasionally, or only in certain situations?

The link in question: https://piefed.social/c/starcitizen/p/1533992/getting-star-citizen-running-on-a-steamdeck-complete-guide

There is an admin setting that requires a user to be logged in before viewing pages on the site. We keep that off normally, but we recently had it on for a couple of days because of over-aggressive scrapers.

When in doubt, you can open that link in a New Private Window so as to bypass your cookie and look at it as a stranger.

Another one I recall is that various instances will require a login for content specifically marked NSFW for any reason.