Time difference between last seen and duration

[eltten]

Hello. I have the following timing problem. In the last seen column is the actual time when the given device was last seen, and in the length column in status does not match the actual. For example, the device that was lost at 10:42 shows that it has been missing for 1h and 20m, and now it is 12:16. The correct one is to show that it has been missing since 1h 34m. The difference is almost 20 minutes in less than 2 hours.

I have two different installations on separate machines. Time rushes to one, and lags behind to the other.

this is screenshot from one of monitoring pages - https://postimg.cc/d7D7gbJ3