I created a SAP Fiori element ALP app based on a reference source CDS View in the SEGW project.
I added a action (function import) to the oData service. The action becomes triggered correctly and I can handle the action in my method implementation "/IWBEP/IF_MGW_APPL_SRV_RUNTIME~CHANGESET_PROCESS" of my _DPC_EXT class.
When I raise an exception (/IWBEP/CX_MGW_BUSI_EXCEPTION) with message container attached, the exception seems to be correctly forwarded by the oData service, but the UI doesn't interpret the exception correctly.
SAPUI5 version: 1.71.16
Thanks a lot for your support.