Graph (bug)

[Zabbbix]

Hey Zabbix-Community,

i created a graph for my memory usage, with the items "vm.memory.size[used]" and "vm.memory.size[free]", with a fixed y value "vm.memory.size[total]".
Unfortunately there are some "bugs" (see the picture in the attached files) in the graph, any idea how i could fix this?

Kind regards

[BDiE8VNy]

Have noticed that too but haven't tracked it yet.
I can imagine that the time for the respective measurements differs in a way, that values not belonging to each are taken for calculation.