Editor crashes clearing existing world after "save current as..."

I’ve been using UE4 4.22 fine for the past month or so and recently upgraded my GPU from an AMD R9 390 to an Nvidia GTX 1070. Now, all of a sudden the editor crashes whenever I try to save current level as and name it something else. It’ll save the level, but when it tries to clear existing level to load the newly saved/named level it then crashes. This happens every time I try to do this making it impossible for me to use this feature anymore. I’ve tried researching this and couldn’t find an answer so I’ll try here. Below is the crash log, and it’s the exact same every single time. This occurs regardless of project, even in a completely new project with nothing in it.

Nothing else other than installing the 1070 has changed on my PC (exact same Windows 10 version, exact same UE4 version, etc.)

LoginId:d820076c4ea588772910fb8155d293dd
EpicAccountId:7ca5aedf746b4ae8b403be74f416ae1e

Assertion failed:
SharedWorldModel.IsUnique()
[File:D:\Build++UE4\Sync\Engine\Source\Editor\WorldBrowser\Private\WorldBrowserModule.cpp]
[Line: 166]

UE4Editor_Core UE4Editor_Core
UE4Editor_Core UE4Editor_Core
UE4Editor_WorldBrowser
UE4Editor_WorldBrowser
UE4Editor_Engine UE4Editor_Engine
UE4Editor_UnrealEd UE4Editor_UnrealEd
UE4Editor_UnrealEd UE4Editor_UnrealEd
UE4Editor_UnrealEd UE4Editor_UnrealEd
UE4Editor_LevelEditor
UE4Editor_LevelEditor UE4Editor_Slate
UE4Editor_Slate UE4Editor_LevelEditor
UE4Editor_Slate UE4Editor_Slate
UE4Editor_Slate
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore user32
user32 UE4Editor_ApplicationCore
UE4Editor UE4Editor UE4Editor
UE4Editor UE4Editor kernel32 ntdll