Arcade Body deltas can be inconsistent during collisions

[samme]

Version

• Phaser Version: 3.15.1

Description

When a body collides with several bodies during a single step, it has correct deltaX() and deltaY() values only during the first collision. On any subsequent collisions during the step, deltaX() and deltaY() are 0.

In the example, this makes friction work correctly only for the first colliding body.

Example Test Code

https://codepen.io/samme/pen/oQxaVb?editors=0010

See the platform's deltaX values in console.

Additional Information

I think this is caused by calling the body's postUpdate method during separation (14d3f6b, #3777).

[samme]

Here's another example. Box collides with 5 balls simultaneously but only 2 balls are moved:

https://codepen.io/samme/pen/vQGvgQ

[photonstorm]

Agreed, it's the reason the mass collide demo doesn't work properly anymore either. Will look into it.