Visualization issues at random time stamps

Hello everybody,

we are experiencing a new bug in our dashboards which we can’t
explain. There are some pictures I uploaded in this mail.

Our use case is that we have 4 different distinct measuring units,
that collect data and send it to our PostgreSQL database.
The measurements go to distinct addresses, so they are distinguishable
from each other.
The weird visualization is happening at a specific time for machines
even though they all are on different data sets.
Deactivating the stacking of the different data points within a or
just displaying single data points solves the problem.
Only if the values are displayed stacked and together at the same
time, the issues comes up.

Do you have an idea what could be the issue?
We are using Grafana v7.5.7 (91de51771c) on a Gentoo system and PostgreSQL 9.6 as Data Source.


Best Regards,
Patrick