I found a bug for pipe inline objects (IO) or only I have such an issue?
If pipe is not strictly verticaly or horizontaly (angle#0 or angle#90) there is a limit for amount of rotation its possible to make ~ 12 times. After that IO become "detached". It remains in the same position, but rotation no longer available and if you delete it (IO) -> pipe (which should be connected to it) won't select. So it's not one (whole) connected system anymore - even hotspots change their behaviour. I tried it on AC22 and AC24 - same result. Of course, you can simply delete IO with connected pipe, then make longer piece of pipe that remains and insert new instance of IO.
This thread probably reveals the same issue, but wasn't been answered...
Agree a bit awkward ( ) to rotate same object more than 12 times, but even more unsual is the fact that after changing positions (i believe that's macros "MEP_m_object_rotator" responsibility) object changes its abilities.