telegraf: MySQL plugin: received error partial write

Relevant telegraf.conf:

# # Read metrics from one or many mysql servers
[[inputs.mysql]]
#   ## specify servers via a url matching:
#   ##  [username[:password]@][protocol[(address)]]/[?tls=[true|false|skip-verify|custom]]
#   ##  see https://github.com/go-sql-driver/mysql#dsn-data-source-name
#   ##  e.g.
#   ##    servers = ["user:passwd@tcp(127.0.0.1:3306)/?tls=false"]
#   ##    servers = ["user@tcp(127.0.0.1:3306)/?tls=false"]
#   #
#   ## If no servers are specified, then localhost is used as the host.
#   servers = ["tcp(127.0.0.1:3306)/"]
#    servers = telegraf@unix
servers = ["telegraf@unix(/var/run/mysqld/mysqld.sock)/information_schema"]
#   
#   ## Selects the metric output format.
#   ##
#   ## This option exists to maintain backwards compatibility, if you have
#   ## existing metrics do not set or change this value until you are ready to
#   ## migrate to the new format.
#   ##
#   ## If you do not have existing metrics from this plugin set to the latest
#   ## version.
#   ##
#   ## Telegraf >=1.6: metric_version = 2
#   ##           <1.6: metric_version = 1 (or unset)
   metric_version = 2
#
#   ## the limits for metrics form perf_events_statements
   perf_events_statements_digest_text_limit  = 120
   perf_events_statements_limit              = 250
   perf_events_statements_time_limit         = 86400
#   #
#   ## if the list is empty, then metrics are gathered from all databasee tables
#   table_schema_databases                    = []
#   #
#   ## gather metrics from INFORMATION_SCHEMA.TABLES for databases provided above list
  gather_table_schema                       = false
#   #
#   ## gather thread state counts from INFORMATION_SCHEMA.PROCESSLIST
  gather_process_list                       = true
#   #
#   ## gather user statistics from INFORMATION_SCHEMA.USER_STATISTICS
  gather_user_statistics                    = true
#   #
#   ## gather auto_increment columns and max values from information schema
  gather_info_schema_auto_inc               = true
#   #
#   ## gather metrics from INFORMATION_SCHEMA.INNODB_METRICS
  gather_innodb_metrics                     = true
#   #
#   ## gather metrics from SHOW SLAVE STATUS command output
  gather_slave_status                       = false
#   #
#   ## gather metrics from SHOW BINARY LOGS command output
  gather_binary_logs                        = false
#   #
#   ## gather metrics from PERFORMANCE_SCHEMA.TABLE_IO_WAITS_SUMMARY_BY_TABLE
  gather_table_io_waits                     = true
#   #
#   ## gather metrics from PERFORMANCE_SCHEMA.TABLE_LOCK_WAITS
   gather_table_lock_waits                   = false
#   #
#   ## gather metrics from PERFORMANCE_SCHEMA.TABLE_IO_WAITS_SUMMARY_BY_INDEX_USAGE
   gather_index_io_waits                     = false
#   #
#   ## gather metrics from PERFORMANCE_SCHEMA.EVENT_WAITS
   gather_event_waits                        = false
#   #
#   ## gather metrics from PERFORMANCE_SCHEMA.FILE_SUMMARY_BY_EVENT_NAME
   gather_file_events_stats                  = false
#   #
#   ## gather metrics from PERFORMANCE_SCHEMA.EVENTS_STATEMENTS_SUMMARY_BY_DIGEST
   gather_perf_events_statements             = false
#   #
#   ## Some queries we may want to run less often (such as SHOW GLOBAL VARIABLES)
   interval_slow                   = "1h"
#
#   ## Optional TLS Config (will be used if tls=custom parameter specified in server uri)
#   # tls_ca = "/etc/telegraf/ca.pem"
#   # tls_cert = "/etc/telegraf/cert.pem"
#   # tls_key = "/etc/telegraf/key.pem"
#   ## Use TLS but skip chain & host verification
#   # insecure_skip_verify = false

System info:

Telegraf 1.9, Ubuntu 18.04, MariaDB 10.3

Steps to reproduce:

A couple of weeks ago I activated the mysql plugin the first time on an Ubuntu 14.04 host with MySQL 5.6.33 and telegraf 1.8 with the config above. Then I eneabled the same config on the new host with newer versions.

Expected behavior:

no error messages

Actual behavior:

2018-11-28T20:51:40Z E! [outputs.influxdb]: when writing to [https://idb.example.com:8082]: received error partial write: field type conflict: input field “ssl_ctx_verify_depth” on measurement “mysql” is type float, already exists as type integer dropped=1; discarding points