koobas.hobune.stream
Prefab mode doesn't show prefab, still shows old scene.
I keep running into this glitch, and other people on our team have run into this problem as well, but I can't seem to see a single person reporting it. It's EXTREMELY annoying, as you can't edit prefabs after this glitch occurs, changing scenes doesn't seem to do anything for it.
Basically, if you're editing and the scene is all normal like this: https://prnt.sc/qlyfeq
But when you double-click a prefab, it attempts to open edit mode, but still seems to not do anything. http://prntscr.com/qlyhfp
As you can see, it's selected and the gizmo should be showing, but the old scene is still there, and no gizmo is showing at all, and if I press f it zooms in on an empty point in space, presumably where the prefab is? I can even still select the objects in the scene that I shouldn't be seeing.
I don't have anything selected as the prefab editing environment either, and setting it to be something didn't change any behavior.
This is very annoying, oh and I'm running Unity 2019.2.17f1.
Any help would be appreciated.
This is certainly not a fix, but a semi-stable working around method is to just make any changes in any script of your solution (using your code editor of choice) and save it, then when unity re-compiles the solution, while the prefab viewing mode is on, it seems to properly load everything into prefab mode and show what it should have done before.
Maybe a hint as to what is going on, but not sure.
Same problem for a long time. Currently running Unity 2019.4.0f1. Very annoying. I spent a lot of time trying to fix and no luck. I am using same workaround as Yazaa - close scene window and open new one. Does anyone know if there is a bug report for this? It must be only under certain circumstances or the forums would be flooded with this issue, but mostly crickets chirping.
Also experiencing the issue here (I'm on 2019.3.2f1).
I have a scene with a simple cube prefab. If I enter the prefab and edit it, I'll keep seeing the scene view cube. Using the Box Collider's gizmos (click on Edit Collider) reveals where my actual prefab is. 
I couldn't find a good repro on my side, but it seems to occur after entering play mode at least once. That means restarting Unity will fix the issue temporarily. My guess is that some internal state in the editor doesn't get properly cleaned. Only by flushing the C# environment does it fix it.
I'm also seeing this in 2019.3.7f. I did recently change the behavior for recompiling when script changes are made, maybe that's related? I can't seem to revert whatever got me into this state.
We've had this issue a while, continuing in 2019.3.13f1. Also if the project is pulled from collab then the prefabs wont load references in-game, we have to manually open each prefab and just update them and then they'll load correctly.
