Hello,
This seems like a bug. I can walk between pipes in some configurations but not others (that would seem reasonable to do).
Please take a look at the screenshot. I tried to draw on top of it the movements that I try to do (in white), and marked in green the one that I can, and in red the one that I can't. Hope that's clear.
BTW this is v0.17.62, just updated.
Thanks!