Shift+o doesn't respect indentation setting (when using Autoindent)

Describe the bug
My indentation is set to spaces. When using o to add a new line below the cursor, it starts indented with spaces but when pressing O (Shift+o) to add a line above the cursor, it sometimes uses tabs instead.

To Reproduce
Steps to reproduce the behavior:

1. Open a new file in VS Code, set indentation to spaces, enable "Vim: Autoindent", and use the following text:

def test():

····print("test")

····return

2. Go to line 3.
3. If I press o, a new line begins below the cursor and inserts spaces:

def test():

····print("test")
····|

····return

4. If I press Shift+o instead, a new line begins above the cursor and inserts tabs:

def test():

→   |
····print("test")

····return

Expected behavior
Respect the indentation setting in all cases.

Screenshots

Environment (please complete the following information):

• Extension (VsCodeVim) version: v1.26.0
• VSCode version: v1.83.0
• OS: Windows 10

Additional context
n/a

Reproduce the issue in VS Code with VSCodeVim using the Python example, spaces indentation, and Vim: Autoindent enabled. Compare the behavior of o and Shift+o, then trace their key handling and verify that both insert the new line using the configured indentation.