I am getting a validation error when importing my MT940 statements.

I can avoid this error if I alter the MT940 statement I am importing and remove the "-" between the sort code/account number and replace it with a "/". However, I am obviously looking to allow the statements to import without making this bank statement amendment.

I have tried a few things such as altering the AccountID formula in data source to only collect the account number and also (MT940 Model) MT940 Bank statement mapping to destination data model (removed "/" in formula and replaced with "-"). May be stabs in the dark but i'm having no luck getting this resolved.


I can't find any documentation online, but wondering if anyone on here has had experience with similar? The rest of the statement imports as expected with this slight amendment.
Thank you!