title: Unity: Changing velocity of RigidBody2D after collision causes game to crash regardless of platform, including in the editor
body: <p>This line of code is single handedly causing my game to crash only sometimes. It essentially freezes the editor and I have to force quit Unity, and same on mobile.</p>
  <pre><code>_rb.velocity = new Vector2(_rb.velocity.x, -20f);
  </code></pre>
  <p>I've tried setting a flag in the collision and updating velocity on the next fixed update. I've tried updating the velocity directly in the EnterCollision2D method.</p>
  <p>Notably I haven't been able to recreate the crash when applying force instead of altering velocity, but applying force doesn't give the desired effect.</p>
  <p>The editor logs don't have anything in them either, so I'm pretty confused. Any help would be greatly appreciated!</p>