Solution : https://service.sap.com/sap/support/notes/163584 (SAP Service marketplace login required)
Key words : 
flag 'spam settings run abap dynpro generation', directory /specific/iscem/v20a/crt_18_20, transaction spam -> extra settings -> turn, /usr/sap/trans/eps/, additional key words cem, 0b /cem v2, car -xvf hp_crt, car -xvf lcp_crt, required comparison modifications, import hp/lcps 18-20
Related Notes : 
       
| 141148 | CEM P3G: Released Hot Packages/LCPs | 
| 132203 | CRT not in SPAM queue | 
| 104127 | @3B@Documentation Hot Package Collections to 4.0B | 
| 97630 | OCS: Familiar problems with patches 3.1H-4.0B | 
| 53902 | Conflicts between Support Packages and add-ons |