NavMeshAgents with same variables acting differently

Hello people!

I'm having a problem and i wonder if you can help me. I'm using NavMesh and some agents to simulate some spheres navigating this relatively simple mesh. The agents' properties can be seen on those tabs at the right. Their scripting is simple: they choose a waypoint (transform) to go to and then they set their destinations.

The problem is: every agent is navigating with a different speed, even though they all have the same speed and acceleration. Some (few) of them navigate normally, but some can't even walk away from their spawners, since they don't have enough speed. I'm not using cost layers or any other collider that should slow them down. The only thing I want is to make them navigate correctly and with the speed they should do it.

Thanks for your attention!