Solution : https://service.sap.com/sap/support/notes/484640 (SAP Service marketplace login required)
Summary : 
      
Key words : 
err         2      bom_post_v2_mat                v2 normal         initfunction module     bom_poststatus              update, module type status         1      bom_post                        v1 nicht nachvb, maximum low-level code 999 reached update termination, maximum low-level code 999 reached, low-level code assignment, report setting indicator mara-kzkup, module id       module, material master record maintenance, bom update terminates, entire bom maintenance
Related Notes : 
       
| 140573 | Low-level code 999 for joint production | 
| 68792 | Collective note for low-level code / recursiveness |