I have 2 items in zabbix version 5. first item as a trapper and it will be updated every one minute and Its value is ascending. second item is calculated based on first item and its formula is : (abschange("KeyName"))/60

for example:
if values of first item are these: 5,8,16,34,68,71,93,102,...
then second item must return: 3,8,18,34,.. Then divide them by 60.

what i get is completely different. i checked in latest data and the first item is always correct and ascending but the second item seems that can't calculate absolute value. how can i find the cause of this problem?

here is an example of what i get:
first item value: 148822441 ,148963574 ,149106618 ,149555694 ,...
second item value: 63498138, 2384, 63498138, 2384,...

i should mention that i had these exact items on zabbix 3 and they worked correctly. after migrating to zabbix 5 i face this problem.