Solution : https://service.sap.com/sap/support/notes/749247 (SAP Service marketplace login required)
Key words : 
client copy including application data ps texts, transaction se11 extras -> enhancement category, table pstxh change table pstxh, table pstxb change table pstxb, se11 extras -> enhancement category, change tab page 'delivery, ps text migration, future client copies 2, sap office integration, attached correction instructions
Related Notes : 
       
| 756776 | PS texts do not exist after client copy II | 
| 667778 | RCTXTCPY: SAPSQL_ARRAY_INSERT_DUPREC with client copy | 
| 601196 | Client copy: Problems with report RCTXTCPY | 
| 578106 | PS text migration to new SAP Office Integration (SOI) | 
| 491923 | CC RELEASE: Client copy errors in Release 6.20 |