[Koha] Adding a repeated subfield with a MARC modification template

Hi I tried to add a repeated subfield with a MARC modification template, but I failed to achieve the wanted result (demo instance 20.11.02) . Could you please tell me if this operation is possible ? The subfield 099$t is repeatable in my framework What I expect is to create a 099$t and add two $t subfields : *099* *_tBOOK_t*CD But the result I obtain is *099 _t*CD (only the 2d occurence is added) I used these 2 rules : Update existing or add new field 099$t with value *BOOK* Update existing or add new field 099$t with value *CD* Regards, -- Mathieu Saby