Created attachment 132673 [details]
ODF file with hanging punctuation (assuming Source Han Sans font is installed)

Hanging punctuation in a vertical document has about as much as a full-width space between it and the character it precedes as opposed to how it is when the text is horizontal. 
ex: 
Horizontal appearance:
けさ早く、
Vertical appearance (note there is no actual space character in the ODF file):
け
さ
早
く

、

Steps to reproduce:
1. Write or paste a Japanese text in a new LibreOffice document.
2. Assuming East Asian Language support is enabled, set the text to vertical going from right to left through Page -> Format -> Text direction.
3. Under Page -> Paragraph -> Asian Typography (again requires East Asian Language Support), check "Allow hanging punctuation"
(If no punctuation is hanging, fiddle with the margins so that at least one period, comma, etc is hanging)

Expected behavior:
No noticeable space between hanging punctuation and preceding character

Actual behavior:
Noticeable gap that is the size of a full-width space between hanging punctuation and preceding character