Hi,
Can you check if any other Mapping using the same target table is executed at the same time?
It might me related to a conflict between several treatments using the same temporary objects (the pre-integration table I_...) in parallel.
If it is the case, you can parameterize the name of the temporary object in your Metadata to use the session id, for instance, to prevent any conflict.
The following article explains how to do it:
stambia.org/doc/77-development-hints-and...-of-temporary-tables