An SMP server I play one is using version 226 and the mechanical and pressurized pipes will stop functioning when their chunk is unloaded then reloaded.

I had left my base to help another player, upon returning, Mechanical pipes that were used to supply water to boilers and steam to a turbine were empty, the turbines were almost dry, the accumulator
couldn't feed water into the pipes and the turbine had shutdown from a lack of steam.

I had to break every single pipe and place them again to get the system back up.
Breaking/Replacing 1 segment doesn't work, the entire netwoork must be replaced
each and every time.

Same server, different player, with screenshots: http://imgur.com/a/WlSgk Also affects universal cables, but oddly always the same ones while others in a different chunk nearby have not had a problem.

We're seeing the same thing on Mekanism 225. Has happened every time we've restarted the server in the past 24 hours.

Fixed in development.

This issue is still present in 8.1.2.229.