Solution : https://service.sap.com/sap/support/notes/1259511 (SAP Service marketplace login required)
Key words : 
enter variable time data, rsqowkex reason, programs rsqiwkex, corrections enable, corrections, prerequisites, 20 minutes, implementing, applications
Related Notes : 
       
| 1352797 | XI runtime: System log if queue is executed twice | 
| 1118297 | XI runtime: QRFC processing of messages |