Do you use nbproc? Do you have dedicated stat socket per process? Otherwise you will just hit the stats socket of a random process leading to this behavior.
This, I think it should to pin the stats socket with the 3 processes, because of this may be the graph shows these behavior.
The documentation says:
stats bind-process [ all | odd | even | <number 1-64>[-<number 1-64>] ] …
Limits the stats socket to a certain set of processes numbers. By default the
stats socket is bound to all processes, causing a warning to be emitted when
nbproc is greater than 1 because there is no way to select the target process
when connecting. However, by using this setting, it becomes possible to pin
the stats socket to a specific set of processes, typically the first one. The
warning will automatically be disabled when this setting is used, whatever
the number of processes used. The maximum process ID depends on the machine’s
word size (32 or 64). A better option consists in using the “process” setting
of the “stats socket” line to force the process on each line.
You know how to setting of the stats socket using the process to force the process on each line? Or another solution to split the values of these 3 processes.