Steps to reproduce:

1. Go to any wiki with a namespace that has both VE and the signature button enabled, e.g. pl.wikipedia.
2. In your preferences, enable VE and set your signature to * my name * (or anything else that starts with a character that has a special meaning at the start of a line), and check "Treat signature as wikitext (without an automatic link)".
3. Edit a page in VE and insert a signature at the beginning of a paragraph.

Actual result: The signature is shown with a * at the beginning.
Expected result: The signature should be shown as list item (which is what happens when you switch to source editing and preview then).