Solution : https://service.sap.com/sap/support/notes/1052689 (SAP Service marketplace login required)
Key words : 
symptom dynamic button menus, opened beforethe buttons, buttons arenow executed, dynamic button menu, sap_basis support package [, navigation bar reason, button menu, navigation button, support packages, incorrectly positioned
Related Notes : 
       
| 563161 | SAP GUI, SAP ITS & SAP IGS patches on Service Marketplace |