Erratic behaviour with multiple crazyflies

[Hurisa]

Hi,

I am launching the multiple_cf_sim.launch file with 4 cfs just as it is in the crazyflie_gazebo pkg.
After takeoff, I launch a node within each namespace (cf1 to cf4) that publishes to the cmd_hover topic of that namespaces with values:

crazyflie_driver::Hover vel;
vel.vx=0.2; vel.vy=0.0; vel.zDistance=0.5;
vel.yawrate=50.0;

However, after a while I start get unstable behaviours for no apparent reason. I attach a link to a video below where this behaviour happens more precisely at 1:08 / 1:48 / 2:07 / 2:15 / 2:20 and 2:58.

https://youtu.be/EOnd7kAexIQ

@Arpafaucon in this issue #8 says such issues might be due to the computer specs, but I'm running this on i7 with 32Gb of ram and none of which is fully used when I check it with htop.

Any help is greatly appreciated.