I've been playing on a new survival world for around a week now, and right after I made it to the Nether I decided to install OptiFine and BSL shaders just to improve my preference of the lighting in the Nether. I haven't experienced any problems relating to the shader pack or OptiFine, so I don't think it's a problem relating to them considering I made a new world in creative with the same seed and went to the same Bastion and the problem wasn't there. Long story short (in the survival world), the Piglins spawned with the Bastion are completely invisible. I have returned to the area from a different angle to try and make sure chunks loaded properly but they are just permanently invisible and I don't know why this is. I have died multiple times trying to return and collect my items but I just start losing hearts and eventually die to the same fate. When I tested it in creative the Piglins were completely visible, so I have no idea what could've caused this other than maybe just a world error with the Bastion spawning? An important thing to note is I have the most recent versions of OptiFine, Forge, and BSL, and I am also not using any resource packs.

The seed for the world is: -5444151076971690299

The Bastion is: -347, 77, 92

The portal coords for the overworld are: -342, 63, -569 to -342, 63, -572 (for the XYZ value not Block value in F3) (the portal is built up from Y63 as well)

Hopefully this is enough information to resolve the issue, as it's slightly frustrating but also very interesting at the same time.

Thank you!