In the following lines of code from __hs_fixup_out_of_order_from_pos, the stop transaction id should be same as the existing value:
/*
* We're going to be inserting something immediately after with the same timestamp. Either
* another moved update OR the update itself that triggered the correction. In either case,
* we should preserve the stop transaction id.
*/
hs_insert_tw.stop_ts = hs_insert_tw.durable_stop_ts = ts;
hs_insert_tw.stop_txn = hs_cbt->upd_value->tw.start_txn;
Also identify why the existing unit tests were unable to catch this bug.