released savepoint blocking further statements

LOG:  00000: execute <unnamed>: SELECT  "position_types".* FROM "position_types" WHERE "position_types"."id" = $1 LIMIT $2 FOR UPDATE
DETAIL:  parameters: $1 = '1401', $2 = '1'
LOCATION:  exec_execute_message, postgres.c:1963
LOG:  00000: process 79469 still waiting for ShareLock on transaction 8453886 after 1000.345 ms
DETAIL:  Process holding the lock: 79440. Wait queue: 79469.
CONTEXT:  while locking tuple (1,139) in relation "position_types"
LOCATION:  ProcSleep, proc.c:1323
STATEMENT:  SELECT  "position_types".* FROM "position_types" WHERE "position_types"."id" = $1 LIMIT $2 FOR UPDATE

[2.] I've tried to use the query Lock Monitoring wiki from to find out what is blocking:

it shows that 79469 | RELEASE SAVEPOINT active_record_2_47 is the current_statement_in_blocking_process. 

https://wiki.postgresql.org/wiki/Lock_Monitoring

SELECT bl.pid                 AS blocked_pid,

         a.usename              AS blocked_user,
         ka.query               AS current_statement_in_blocking_process,
         now() - ka.query_start AS blocking_duration,
         kl.pid                 AS blocking_pid,
         ka.usename             AS blocking_user,
         a.query                AS blocked_statement,
         now() - a.query_start  AS blocked_duration
  FROM  pg_catalog.pg_locks         bl
   JOIN pg_catalog.pg_stat_activity a  ON a.pid = bl.pid
   JOIN pg_catalog.pg_locks         kl ON kl.transactionid = bl.transactionid AND kl.pid != bl.pid
   JOIN pg_catalog.pg_stat_activity ka ON ka.pid = kl.pid
  WHERE NOT bl.GRANTED;

 blocked_pid | blocked_user | current_statement_in_blocking_process | blocking_duration | blocking_pid | blocking_user |                                           blocked_statement                                           | blocked_duration 

-------------+--------------+---------------------------------------+-------------------+--------------+---------------+-------------------------------------------------------------------------------------------------------+------------------

       79469 | boga         | RELEASE SAVEPOINT active_record_2_47  | 00:10:44.781475   |        79440 | boga          | SELECT  "position_types".* FROM "position_types" WHERE "position_types"."id" = $1 LIMIT $2 FOR UPDATE | 00:08:39.344037

(1 row)

[3.] But according to pg logs that statement that RELEAS SAVEPOINT was executed fine:

LOCATION:  exec_execute_message, postgres.c:2034
LOG:  00000: statement: RELEASE SAVEPOINT active_record_2_47
LOCATION:  exec_simple_query, postgres.c:946
LOG:  00000: duration: 0.038 ms