Can't seem to get a valid value with diskio_read_time and diskio_write_time when using Prometheus

Hi everyone!

As title says -

Relevant telegraf.conf:
Everything’s default within [[inputs.diskio]]

System info:
[Include Telegraf version, operating system name, and other relevant details]
Telegraf 1.4.3
CentOS Linux release 7.4.1708 (Core)
Prometheus 1.7.1

Steps to reproduce:
Trying to use the following metric query leads to value which is more than 100%:
irate(diskio_read_time{host=~"$host", name!~“dm-."}[5m])/1000
irate(diskio_write_time{host=~"$host", name!~"dm-.
”}[5m])/1000

What could possibly be wrong?

Thanks,
Dror.

bump, did anyone experience this too?