Different Character sets may cause string data types to be translated to BYTE columns instead of CHAR columns for Replicate's temporary change tables. This can result in size mismatches that will cause the task to fail even though the source and target columns are set to varchar2 with the same max length.
00001640: 2017-10-31T15:06:40 [TARGET_APPLY ]E: ORA-12899: value too large for column "DM_OWNER"."attrep_changesAC8E40BB_0000121"."col26" (actual: 27, maximum: 23) [1020417] (oracle_endpoint_load.c:1054)
On your Oracle target endpoint connection, navigate to the advanced tab and open the internal parameters setting.
Add internal parameter "charLengthSemantics" with value "CHAR". This parameter will change the column data type creation back to CHAR to resolve the size mismatch.
The task needs to be stopped and resumed for the new internal parameter to take effect.
Cause
Oracle source character set of WE8ISO8859P1 replicating to Oracle target with character set AL32UTF8 is known to use BYTES as the data type instead of CHAR.