Zolin and Zelinda stuck progression - bug

Last boss of Interlude act. Zolin and Zelinda, 2 Priests. They stuck talking the spells and nothing is happening. can't progress any further. Stuck happened after first failed attempt to kill them.
All they do are talking to each other in Maori e.g. Kuxte' kfinil'! Tlaxye' le something and it's endless.