Why does Master think it's a Slave on Reboot?

In a simple MySQL replication Master-Slave configuration I have a problem where Master tries to connect to itself as a slave on reboot.

So when I restart MySQL on Master, I see errors related to the same server trying to replicate to itself and I have to manually run mysql -e "STOP SLAVE;" every time I restart MySQL.

How can I disable slave on master for good?

Here's the relevant portion of my.cnf:

## Logging
binlog_format                   = mixed
log_bin                         = /var/log/mysql/mysql-bin.log
sync_binlog                     = 1
pid_file                        = /var/run/mysqld/mysqld.pid
log_error                       = /var/log/mysql/error.log
#general_log                     = 0
#general_log_file                = /var/log/mysql/general.log
slow_query_log                  = 1
slow_query_log_file             = /var/log/mysql/slow.log
long_query_time                 = 3
expire_logs_days                = 14

sql_mode                        = STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
# sql_mode                        = ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

## Replication
server_id                       = 200

## Master Configuration
binlog-do-db                    = my_db_1
binlog-do-db                    = my_db_2
binlog-do-db                    = my_db_3
binlog-do-db                    = my_db_4
binlog-do-db                    = my_db_5
binlog-do-db                    = my_db_6

Also, when I run SELECT * FROM mysql.user; I don't see the repl user that's allegedly a "slave" on Master.

Here's an example of the errors I see on Reboot (before I run STOP SLAVE; on Master):

2016-09-01T15:22:23.845505Z 384 [Note] Access denied for user 'repl'@'192.168.100.200' (using password: YES)
2016-09-01T15:22:23.845761Z 1 [ERROR] Slave I/O for channel '': error connecting to master 'repl@192.168.100.200:3306' - retry-time: 30  retries: 8, Error_code: 1045
2016-09-01T15:22:50.191636Z 0 [Note] InnoDB: page_cleaner: 1000ms intended loop took 6843ms. The settings might not be optimal. (flushed=15210 and evicted=0, during the time.)

Apart from this, replication is running fine. Writes to Master show up flawlessly on the real, read-only, Slave.