The value of the rs_origin_commit_time system variable depends on whether you are using the parallel DSI feature.
If you are not using parallel DSI to process large transactions, the value of rs_origin_commit_time contains the time when the last transaction in the transaction group committed at the primary site.
If you are using parallel DSI to process large transactions (before their commit has been read from the DSI queue), when the DSI threads start processing one of these transactions, the value of rs_origin_commit_time is set to the value of rs_origin_begin_time.
When the commit statement for the transaction is read, the value of rs_origin_commit_time is set to the actual commit time. Therefore, when the configuration parameter dsi_num_large_xact_threads is set to a value greater than zero, the value for rs_origin_commit_time is not reliable for any system function other than rs_commit.