Had an odd bug which only occurred once so far. Pip boy did not show up at all. Even on cell transhion. Ultimately had to reload client to resolve. Area was some area of a root cellar.

happened 2 me twice just keep on switchin from 1st ro 3rd person and it will eventually resolve, at least for me

I had the same problem

Turned off PC and launched the game.

now it works

Happened to me when my HDD was busy in the background. Avast, and something else kicked in. Once they stopped and I went back into the game it worked.

I think it's an issue with loading speed of textures from the HDD.

Does anybody who had the issue have the game installed to an SSD?

I am running the game on a solid-state and didn't see anything different in disk usage. In my case my hands and weapon disappeared as well as my pip boy.