2531852 - ITAB_DUPLICATE_KEY in XPRA phase

During XPRAs phase in and Upgrade or Update (Support Packages / Enhancement Packages), the following error takes place:

2 EPU122XPost-import method "FDT_AFTER_IMPORT_C" started for "FDT0000" "T", date and time: "20170907201352"
1AETR012XProgram canceled (job "RDDEXECL", number "20135200")
1AEPU320 See job log"RDDEXECL""20135200""SP3"
1 ETP162 EXECUTION OF REPORTS AFTER PUT
1 ETP110 end date and time : "20170907201407"
1 ETP111 exit code : "12"
1 ETP199 ######################################

A dump in ST22 has the following information:

Error analysis

An attempt was made to insert an entry into table
"{O:3009!\CLASS=CL_FDT_TYPEDESCR*\CLASS=CL_FDT_ELEMDESCR}\DATA=MS_TEXT_BUFFER-
TS_TEXT". Updating
unique table key "PRIMARY_KEY" resulted in a duplicate entry however. The key in
question could be either the primary key or a secondary key.

• SAP enhancement package 1 for SAP NetWeaver 7.3
• SAP Netweaver 7.4
• SAP Netweaver 7.5

IF_FDT_ADMIN_DATA, GET_TEXTS, GET_DDIC_TEXT, XRPA, post-implementation steps, SAP_BASIS SP , KBA , BC-SRV-BR , BRFplus - ABAP based Rule Framework , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem