How to smooth the seams between the colliders?

I’m doing the game. Level I is assembled from sections (here by the way, a similar example, here, too, of the sections Mini Golf Starter Kit | 3D Characters | Unity Asset Store). The problem is that at the junction of these sections the ball bounces. And I tried to put the section so that would colliders were right next to each, other. and one that would overlap one. Tried and mesh collider and box collider. Does not help. If anyone knows how to solve this problem will be very grateful for your help.

it seems no one knows :-((