A contribution batch containing transactions of more than one currencies causes fatal error
I believe the standard workflow for accounting requires a single currency per batch. At least that was all that we aimed to support. Please create an issue at lab.civicrm.org indicating that there should be a 'friendly' error message preventing transactions that have a different currency from ones already in the batch from being added. This should include an error in case of an attempt to simultaneously add transactions in more than one currency.