So far this has happened every time I've left the area and come back. It's happened a few time already.
Here's a screenshot of what it looks like. Light hasn't updated yet at this point:

Do you have any logs?

Also does this happen on the latest version(s), or also on the previous ones?

No logs or anything.. Only happens in 0.8.15. I downgraded to 0.8.12 and it hasn't happened since!

Do you have this issue in 0.8.13?

Actually, can you test on Forge 2014 and see if you have the issue?

Also I'm hoping this may be a step in the right direction to figuring out why certain parts of the storage network disconnect at random!

Yep, I will try this in a bit! Sorry for the late response.

@BootyToast
I just read this on the #minecraftforge IRC, maybe try update Forge to the latest version...

I will try this, man! I tried testing the issue with an earlier forge but there were some issues downgrading with other mods. Gonna update and will report back in a bit!

I did update Forge to 2046, but it seems anything past Forge 2031 breaks more things than it fixes. A lot of people are reporting crashes with breaking certain blocks in Tinkers Construct among many other mods, so unfortunately I'm not able to use the current version. D:

Edit: Although I will say that Forge 2046 fixed the disappearing controllers. Did not fix networks disconnecting though. Sorry to be a pain in the butt.

Yes, the network disconnecting is kinda of an unrelated issue. But good to hear it is fixed now!

(Btw, you should be able to use the RS upgrade in an old Forge like 2014 as well, before it was buggy :P)