Voltage incorrect data in new version on 12 Voltage systems

Hi Mikrotik guys, i find the problem if RB is on 12 Voltage then SNMP show 28V stable value after changing ROS from 3.27 to 4.13 can you repair it, please? There is a RB 433AH. On 24 Voltage system it seems good afret upgrade from 4.6 to 4.13 there is a RB 450G. Monitored value on booth systems are on attachment. Thank you, Yarda.
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@yarda
sorry if i off topic but what software do you use for that monitoring? because i am looking one for myself, i was testing cacti but doesn’t work well on freebsd.