- Why the pipe component breaks the pipe at this location?!

Pipe relies on continuity I believe, or it makes a kink. My guess is it can’t figure out how the kink should be at those breaks (kink is like a miter that is a degree between the two segments, so a 90 degree kink would have a 45 degree miter). Since it seems the explode component shows discontinuity there it means that the continuity of the curve is broken there, even if you can’t notice it by eye.

- Is it possible find the breaking points/connections before and split the curve at these points to solve the problem?

The explode component as you have done or try the discontinuity to test for different kink types, maybe also the curvature graph, the solution would be to make a better curve, why is simplify not an option? Have you tried to use fit curve?