Hello,
Check version of EA-FINSERV components. On EHP7 it must be 617. If not - ask your basis team to upgrade component.
in tr. SFW5 - business function FIN_TRM_LR_FI_AN_3 must be activated: https://websmp201.sap-ag.de/~sapidb/011000358700000726692010/ - FIN_TRM_LR_FI_AN_3: Additional Account Assignments (New) paragraph.