*edited to more concisely explain the issue
APEX 21.2.0 and 21.2.7 (both with ORDS 21.4.3 standalone) and APEX 22.1 (with ORDS 22.1.0.r1051723 deployed via tomcat9). I've not tested in other versions but this issue might exist in other versions.
Databases are 19.3c, 19.14c, 21.5c respectively
What is happening:
SQL Workshop -> Utilities -> Data Workshop -> Load Data OR...
SQL Workshop -> Object Browser -> Data -> Load Data
When APEX Data Load auto maps from a csv (csv's column headings match the existing target table's timestamp column), APEX fails to Load Data with error ORA-01843 not a valid month.
nls_timestamp_format = DD-MON-RR HH.MI.SSXFF AM
sample timestamp data = 21-JUN-20 06.45.19.434901 AM
Target table's column type = TIMESTAMP(6) WITH LOCAL TIME ZONE
My Workaround
If we force APEX not to auto map to TIMESTAMP table columns (change csv column heading not to match target table's timestamp column) and if we manually "configure" map to the target timestamp table column, it works without error and data loads.
Name the csv column heading in the file differently (append an "X" to end of column heading name) differently than the target table column to prevent APEX trying to auto map to the timestamp table column. If we manually map the column it works! If we let APEX auto map the timestamp column when heading and column names match then APEX LOAD DATA fails with ora-01843
*Attached is a sample .zip containing two csv files (one that fails and one that succeeds to load) and also a script file to create a dummy table for testing. Try using APEX Data Load and see what happens.
APEX_Load_from_csv_into_timestamp.zip (815 Bytes)