Goodmorning, I've noticed that Delta (simple change) value in Item configuration produces wrong values.

I have a zabbix trapper item and i send some values:

zabbix_sender -z server -s "host " -k key -o 117800000
zabbix_sender -z server -s "host " -k key  -o 117800001
zabbix_sender -z server -s "host " -k key  -o 117800005
zabbix_sender -z server -s "host " -k key  -o 117800012
zabbix_sender -z server -s "host " -k key  -o 117800014

I expect that "key" item values will be:

1
4
7
2

because of Delta. Instead result is

1
117800004
8
117800006

and produces a graph like this:

Can you please solve?

I have zabbix 3.2.11

Thanks