Hello
I want to import a set of Stories in my Jira project using CSV import.
I have a custom field (Portal) that can have multiple values (Partner and Operation).
When I import a single value in the field, I don't have any issue
But when I try to import multiple values, I have an error message.
I tried both ; and , separator but each time I have an error message
The value [ {null=Partner,Operation} ] can't be added to the Custom Field [ Portal ]. The value [ {null=Partner,Operation} ] can't be found or is in the incorrect format
Extract of my csv file:

My Portal field configuration

Can you confirm this should be possible ? If not, how can I import/update multiple values in a field ?
Thanks for your feedbacks