Unity physics making ball bounce unexpectedly after a certain collision occurs.

We have a game with Mini Golf concept. We have levels made with modular objects.

So far we were using Unity 2018.1 & 2018.2 for release builds and everything was working fine for us. But recently google stopped accepting .APK files for production so we tried using Unity 2018.3x version to use App Bundle and we found following physics related bug.

https://www.dropbox.com/s/gm5qv9wr0n9g0q5/Unity Bug.mp4?dl=0
(This video is recorded in Unity 2018.3.8)

Bug explanation :

- When ball hits the edge of end hole, the unexpected bounce bug is started in entire level whenever 2 objects are placed in sequence. If the ball does not collide with end hole border, everything works fine. Means after one certain type of collision in edge occurs, all edge collision & bounce get malfunctioned.


I tried following methods to solve this problem :

- Tweaking physics settings, specially contact offset, bounce threshold, contact generation etc

- Changing bounce values in physics material

- Changing mesh collider cooking options

- Changing normals settings in import settings of mesh collider fbx files

- Tried using unity primitive cubes & primitive colliders

- Tried with Unity 2018.3.0, 2018.3.8, 2014.6 (LTS), 2019.0 but this bug remains the same in these versions

But nothing from above helped me solving this bug. We cannot push any new release until we solve this problem.

This bug happens in any unity version starting from 2018.3x or higher, but up to 2018.2x it works perfectly fine.