Here's an archived version of the Microsoft Knowledge Base article about the bug:
Outlook Express: https://www.betaarchive.com/wiki/index.php?title=Microsoft_K...
Outlook: https://www.betaarchive.com/wiki/index.php?title=Microsoft_K...
Outlook Express: https://www.betaarchive.com/wiki/index.php?title=Microsoft_K...
Outlook: https://www.betaarchive.com/wiki/index.php?title=Microsoft_K...
Seems sensible.
The bug here was not "begin" followed by two spaces, but rather its "begin" followed by some other text followed by two spaces, which if i recall correctly is exactly what Microsoft would auto-format your text to.