SugarCube's @-directive not properly working with the alt attribute?

Question

I am using imagemaps to create a point-n-click travel function.
My <<waypoint>> widget places a geo-tag image above an underlying map-image, and using the @-directive to supply data for the <img> usemap & style attributes (works perfectly).

However, issues arise in the accompanying <map> tag. The name, title & data-passage attributes work as intended, but I never get the tooltip-popup from the alt-attribute. I do require this as a means of knowing which location is which before venturing there.
Outside of the widget, with hardcoded values, I do get the alt-popup.

My waypoint-widget

<<widget "waypoint">>
	<<set $waypointlocation = $args[0]>>
	<<set $waypointsimple = $waypointlocation.replace(/'|\s/g, '')>>
	<<set $waypointsimple = $waypointsimple.toLowerCase()>>
	<<set $waypointhash = "#"+$waypointsimple>>
	<<set $waypointxy = $args[1]>>

	<img src="https://i.imgur.com/Rg43Fwe.png" @usemap="$waypointhash" class="overlaywaypoint" @style="$waypointxy">

	<map @name="$waypointsimple">
    	<area target="_blank" @alt="$waypointlocation" @title="$waypointlocation" @data-passage="$waypointlocation" coords="16,30,25,10,20,1,11,1,8,10" shape="poly">
	</map>
<</widget>>

and I'm calling the widget with:
<<waypoint "Braxton's Goods" "top: 250px; left: 85px;">>

Answer 1

Alright, jumped the gun a bit.
Haven't updated SugarCube in a long while, and I found http://twinery.org/questions/45452/attribute-directive-to-make-variables-tooltips?show=45459#a45459 whilst browsing around similar issues. (If only I had found it before posting this thread)
Updating SugarCube to 2.28.8 fixed it

Comments

You may notice that many of the features described in the story format's documentation contain a section titled Since: and that that section will contain one or more version numbers.

These version numbers indicate the minimum version of SugarCube 2.x required for that feature to be available, if a feature has no such section then it means that it is available in all versions of SugarCube 2.x

eg. the documentation for Attribute Directive mark-up includes

Since:
    v2.21.0

In this specific case, as indicated in the reply you linked to, there was a bug in the feature's implementation which was fixed in a later version.

note: I have informed the story format's developer about the lack of clarity in this feature's Since: section.