3675394 - Fiori Report Shows Error "Specify a value for variable <name>" (BRAIN 629) though the Mandatory Variables are already Filled

When executing a Fiori report, error messages "Specify a value for variable <name>" (Message No. BRAIN 629) are shown for mandatory variables though they are already filled with valid values. This happens especially after doing value help for a hierarchy node variable.
When ignoring the error and just clicking "Go", the report is executed successfully.

S/4HANA

BRAIN 629, BRAIN629, BRAIN-629, F4 help, LOV, input help, value help, hierarchy node variable , KBA , BW-BEX-OT-OLAP-VAR , Using Variables , BW-RUI-FPM , FPM Analytical GUIBB , Problem