Lots of other symbols validate as tags, including curly and straight quotes in the sample below.
Wonder what properties makes of them in 1.4.x
---
tags: [test.ing, work;ing, do:ing, lov*ing, say"ing, play'ing, hop’ing, slop”ing,]
---
EDIT
Perhaps ties in with this:
Alias wrapped in quotation marks splitting at comma - Bug graveyard - Obsidian Forum
The same thing happens with
tags.
And:
To repeat myself in the bug report, the current behavior is not standard.
(Not referring to tags directly but insinuated from the first link.)
And:
In v1.4, this divergence from the standard is being addressed. We will begin with rewriting the incorrect form to a compliant one and eventually (at some point in the future) stop supporting the incorrect format.
(Not referring to tags directly but insinuated from the first link.)