Looks like its an issue with dojox.dgauges.components.DefaultPropertiesMixin
. If you replace the _setValueAttr function to
_setValueAttr: function(v) {
this.getElement("scale").getIndicator("indicator").set("value", v);
}
it should animate for you.
As a side note, all the other functions in DefaultPropertiesMixin
sets each property directly instead of using the set function. It might be advisable to change them to use the set function instead.