Have you experimented with changing any of the Anchored Object Options for the document?
Have you tried to change kerning and tracking?
In order to assign the boxes to the center of the corresponding character we have make 8 different object styles (the plugin "reads" the character and "decides" which to choose). So the Anchored Object Options already vary.
Nevertheless, I tried to change them, but is no solution...
Because of the design of the font any almost change to tracking destroys completely the ligatures.
I tried to change kerning but nothing...