Going down in a double ended pipe breaks many things in a vertical level

[city41]

repro:

1. create a tall level, in the 60's height wise
2. place a double ended pipe just at the beginning of the level
3. play the level, go up the pipe then back down

here is a level that repro's the problem

expected: goes back down as normal
actual: camera goes bonkers, Mario disappears, game really breaks

double ended pipes have lots of gotchas and failures. Need to learn more about them in general.