Can you click on her portrait to switch to Madora? Does she show up in the list of portraits at the top of the screen in combat?
Please email supportdos@larian.com, with a description of the problem and the report.zip file generated by the
D:OS support tool (for the PC version). The report will contain system and game information, any crash dumps, and your saved games. If file size is an issue, you can delete all the saves other than one before this encounter (and maybe leave one before the previous fight, where Madora was included).