When using the Feline origin, at a certain time during the day, the game goes completely black minus your hand and any blocks you're holding. Looking around occasionally causes the terrain to pop back up. Thought it may have been the Total Darkness mod, but it's been uninstalled for a while and it only seems to happen with this origin.

Hey there, thanks for the bug report. I have a friend on a server who has been playing Feline for a while now and has not experienced this bug. I also tried to reproduce it by choosing the origin and watching through a whole cycle of day and night, but no luck.
Are you using any other mods? Did you do anything specific when this happened? Is it possible for you to provide a log file for me to take a look at?

Since it happens in-game, and it doesn't directly lead to a crash, the possibility of a log file containing anything useful is slim. The only mod I have that could possibly cause an issue is Sodium, since it changes rendering directly.

Hmm, interesting. The friend I mentioned also uses Sodium, so it can't really be that. Even though the other mods might not have anything to do with it, it would still be helpful to know which ones you use, so that I can try to reproduce it.
Which time of the day does this seem to happen to you? Does it happen every day?
Is it still possible for you to provide a log file? Otherwise I have nothing to go on with this bug, and having a "slim possibility" of something useful is better than none. ;)

Any more information on this? Are you able to consistently reproduce this bug, or has it not happened again?

If not, then I will assume it's not a problem any more and close this issue.

Having the same visual bug when my buddies fly around with the elytra class, having a hard time narrowing down the issue to a mod - I suspect some combination with optifine, immersive portals, crimson moon and this mod, @VolgrimDCLXVI what mods were you using and did you eliminate this issue

Removing crimson moon and immersive portals seemed to fix the issue, still curious to hear what mods were on the install of the OP

I actually started up a new job the day after posting this, so I didn't get much time to figure out what it was/respond. It's linked to something that modified the Night Vision effect, though. I don't use Immersive Portals (as I have Sodium) but I do use Crimson Moon.

I also came across this issue with the Feline origin in my personal modpack which causes the rendering bug pictured below. This happens only at night, presumably when the Nocturnal power is supposed to activate. This bug can be reproduced on a fresh 1.16.1 fabric install with just Origins (0.3.4) and Clear Skies (1.4.44) mod installed. Use the command /time set 13500 and wait a few seconds for the bug to appear. I also started a new issue in the Clear Skies repository here.