The result will be NaN, if dx1===0 (GetLineToLine.js)

[finscn]

https://github.com/photonstorm/phaser/blob/c5d53f9e94928746770176ea1db3d29b495b9b05/src/geom/intersects/GetLineToLine.js#L66

if (x3 + dx2 * t - x1)===0 and dx1 === 0, u & s will be NaN.
then the out.x & out.y will be NaN

[zekeatchan]

This issue has been resolved.

We have investigated the problem and have implemented a solution to check whenever dx1 or dy1 values are zero.

The fix will be reflected in the next Phaser update.