inputs.ping native sends wrong number of pings

[bjoe2k4]

Relevant telegraf.conf:

[global_tags]
[agent]
  interval = "10s"
  round_interval = true
  metric_batch_size = 1000
  metric_buffer_limit = 10000
  collection_jitter = "0s"
  flush_interval = "10s"
  flush_jitter = "0s"
  precision = ""
  debug = false
  quiet = true
  logtarget = "file"
  logfile = "/var/log/telegraf/telegraf.log"
  logfile_rotation_interval = "1d"
  hostname = ""
  omit_hostname = false
[[outputs.prometheus_client]]
  listen = ":9283"
  metric_version = 2
[[inputs.ping]]
urls = ["vodafone.de" ]
count = 5
method = "native"
ping_interval = 0.2
timeout = 4.0

System info:

RaspberryOS with a 4GB Raspi4
Linux raspi-pihole2 5.4.72-v7l+ #1356 SMP Thu Oct 22 13:57:51 BST 2020 armv7l GNU/Linux
Telegraf 1.16.2 (git: release-1.16 962082f) (offical release)

Steps to reproduce:

1. Set above config & start telegraf + prometheus
2. Wait for a day

Expected behavior:

telegraf sends and receives exactly 5 packets every 10s when there is no packetloss.

Actual behavior:

telegraf sometimes seems to send more packages than it is supposed to (6 instead of 5)

The question is if the 6th packet is actually sent or if it is just a reporting bug. A 100% correlation with a packetloss of 16.66% rather points to a bug.

Additional info:

[reimda]

Do you get the same behavior with ping method = "exec"?