Drivetrain Motor Issue

Before I address the issue, I just want to be clear that our drivetrain is a 4 motor V5 drive
There seems to be a problem with our drivetrain in the fact that the left side stalls completely after a while when the robot drives forward. To be more specific, when we move the robot forward with the left and right joystick on the V5 controller, it goes straight for 3 seconds before it starts to turn left even though both joystick controls are pointed in forward direction. After we move the controls back to neutral, let the robot rest for 1-2 seconds, and drive straight again with both joysticks, the same problem repeats itself. This has been happening continuously and we have no idea where it’s coming from. Any ideas on what this is and how to fix it? Thanks!

  1. Friction on the left side of the robot.
  2. Motor issue on the left side of the robot.
  3. Something else.