Problem diagnosed and solved. It was a font issue. Will be corrected in next release.
Meanwhile, to fix it in your copy follow these steps:
— open file "ist.clo" in foler "unlthesis-files/ChapStyles"
— replace line 11 from
\font\ch@pnamfont=cmr8 at 8mm % computer modern bright
to
\font\ch@pnamfont=ebmr8 at 8mm % computer modern bright
Try again. Hope it works now! :)