[Level/Prefab (backpack) Toolbelt error Loop]

Worth a shot, try deleting your "Empty" folder in your Saves directory.  See example link below.

 

C:\Users\<user profile name>\AppData\Roaming\7DaysToDie\Saves\Empty

 

The Empty folder is specifically used by the prefab editor.  Deleting it will reset any toolbelt / character equipped items when in the prefab editor that could be causing the error.

[downtown_strip_04 zombie spawns in area already checked by player]

That is working as designed.  He crawled out of the open vent. 😎

[downtown_filler_13 key rack issue]

Thanks, this will be fixed in a next build.