My findings:<br>
<b>Slow running query:</b>
<pre>
            ---------------------------------------------------------------------------------------------------------------------------------------------------
            | Id  | Operation                                         | Name                          | Rows  | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
            ---------------------------------------------------------------------------------------------------------------------------------------------------
	    |  48 |                 PARTITION RANGE ALL               |                               |     1 |    82 |    34   (0)| 00:00:01 |     1 |    17 |
            |* 49 |                  TABLE ACCESS BY LOCAL INDEX ROWID| ADIO_UNIVERSOS                |     1 |    82 |    34   (0)| 00:00:01 |     1 |    17 |
            |* 50 |                   INDEX RANGE SCAN                | IXN_ADIOUNIVERSOS_ARINOPERLOC |  2039K|       |    34   (0)| 00:00:01 |     1 |    17 |
		
              49 - filter(("AU"."PROGRAMA_ID"=1 OR "AU"."PROGRAMA_ID"=2) AND "AU"."CARGA_VALIDA"=1)
              50 - access("AAI"."ID_ARCHIVO_INSUMO"="AU"."ID_ARCHIVO_INSUMO"
              
</pre>

<b>Fast running query:</b>

<pre>
            ---------------------------------------------------------------------------------------------------------------------------------------------------
            | Id  | Operation                                         | Name                          | Rows  | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
            ---------------------------------------------------------------------------------------------------------------------------------------------------
            |* 29 |              TABLE ACCESS BY GLOBAL INDEX ROWID    | ADIO_UNIVERSOS                |     1 |    71 |     2   (0)| 00:00:01 | ROWID | ROWID |
            |* 30 |               INDEX UNIQUE SCAN                    | PK_ADIOUNIV_IDUNIV            |     1 |       |     1   (0)| 00:00:01 |       |       |
       		
              29 - filter("AU"."CARGA_VALIDA"=1)
              30 - access("AU"."ID_UNIVERSO"="PPU"."ID_UNIVERSO")

</pre>

I found that the table 'ADIO_UNIVERSOS' is accessed by local index 'IXN_ADIOUNIVERSOS_ARINOPERLOC'(INDEX RANGE SCAN) which has returned 2039K rows, scans several partitions(1-17) and in the fast running query the same table is accessed by global index 'PK_ADIOUNIV_IDUNIV'(INDEX UNIQUE SCAN) has returned 1 row, which doesnt run through all the partitions.<br>
Index Range Scan obviously returns more rows than Index Unique Scan. Here in the Slow running plan Index Range Scan is influencing the Nested Loop(Cost 269).