I've read around the internet that other players are having similar issues, and I hope there is a way to address it.

So during the Trinity Tower mission where you can recruit Strong, I was going down the lifts that were on the edge of the building when I guess my current companion Nick Valentine got stuck somewhere around the building. Once I got to the bottom of the building, I accepted Strong to become my current assigned companion. I then sent Nick to Sanctuary.

After playing some more of for a couple hours, I noticed that Nick wasn't back to the settlement. Sure enough, I check back at Trinity Tower and he's still there, stuck somewhere I can't seem to reach.

As such, I'm hoping Bethesda can patch the game so companions will teleport or something back to the settlement they've been sent to in case things like this ever happens where the companion gets stuck in the environment and can't walk their way back. Or maybe even allow mods for the PS4 version of the game. USB keyboards do work for the system after all.