Oracle unique constraint error completing inventory movement

[Fabio Canella]

I've found a problem similar to
https://idempiere.atlassian.net/browse/IDEMPIERE-2421

but in this case the error occours completing an internal inventory movement

ORA-00001: unique constraint
(ADEMPIERE.M_INVENTORYLINEMA_KEY) violated

in this case I solved changing
ma.saveEx();
to
ma.save(get_TrxName());

in the class MInventory.java, method checkMaterialPolicy