VBScript permission denied error 800A0046 in CreateTextFile suddenly started occurring - vbscript

Question

I have been using a particular VBScript for a long time and it suddenly broke today with a permission denied error. The line number referenced as the error points to a call to CreateTextFile as the problem. I have simplified the script to 4 lines and still get the error. Here is the simplified 4 line script:
Set objFS = CreateObject("Scripting.FileSystemObject")
Set objOutputFile = objFS.CreateTextFile("test.txt", True)
objOutputFile.WriteLine("test")
objOutputFile.Close
When I run this script I get:
Line: 2
Char: 1
Error: Permission denied
Code: 800A0046
Source: Microsoft VBScript runtime error
This is on a stand-alone Windows 10 PC, and I have changed nothing to do with user or file system permissions on my computer and have not modified the script prior to its breaking.
Just for grins, I verified that System, Administrators, and my user ID all have Full, Modify, Read & execute, List folder contents, Read, and Write permissions. That all looks good. I can copy files, delete files, open notepad and create or edit files, etc., so it doesn't seem to be a permissions problem.
It only seems to affect writing to my user profile. For example, if I run the following code, it fails in line 5, not line 2:
Set objFS = CreateObject("Scripting.FileSystemObject")
Set objOutputFile = objFS.CreateTextFile("C:\Temp\test.txt", True)
objOutputFile.WriteLine("test")
objOutputFile.Close
Set objOutputFile = objFS.CreateTextFile("C:\Users\Username\Documents\Test\test.txt", True)
objOutputFile.WriteLine("test")
objOutputFile.Close
I can work around the problem by doing the following, but I should really not have to do this:
Set objFS = CreateObject("Scripting.FileSystemObject")
Set objOutputFile = objFS.CreateTextFile("C:\Temp\test.txt", True)
objOutputFile.WriteLine("test")
objOutputFile.Close
Set objShell = WScript.CreateObject("WScript.Shell")
objShell.run "cmd.exe /C copy ""C:\Temp\test.txt"" ""C:\Users\Username\Documents\Test\test.txt"" "
What gives? Has Microsoft changed something that broke writing files with VBScript?
Thanks!