[1.8.9][CC 1.78][SMP] "No wireless modem attached" error when modem is attached

VERSION:
MC 1.8.9 (Forge 11.15.1.1722)
CC 1.78

DESCRIPTION:
After a server reset (chunk unload/reload), labelled turtle fails to detect its wireless modem:

"No Wireless modem attached"

EXPECTED RESULT:
Not receiving this failure message

REPRODUCTION STEPS:
I'm not exactly sure which of these steps are relevant, but this is what I did:
Crafted a turtle from an advanced computer, a crafting bench, and a diamond axe
Labelled the turtle "Treefeller"
Swap crafting table with a wireless modem (turtle.equipLeft())
Rebooted the server

I've found two ways to resolve this error (temporarily)
Unequip and reequip the modem (turtle.equipLeft())
Break the turtle and replace it

SCREENSHOT/VIDEO:
Picture of the error:


Picture of the turtle with the ender modem:



Sometime in the next week I'll try things like re-labelling the turtle, or just making a new one.

Any other mods in use?

Your modem is off (it is not lighting red)
try to turn on with

rednet.open("left")

COOLGAMETUBE, on 28 March 2016 - 06:17 PM said:

Your modem is off (it is not lighting red)
try to turn on with

rednet.open("left")

The gps program doesn't use rednet, and already does modem.open on its own.
I've had the same problem before on a cauldron server, can you try if it also happens in singleplayer?

COOLGAMETUBE, on 28 March 2016 - 06:17 PM said:

Your modem is off (it is not lighting red)
try to turn on with

rednet.open("left")

The modem isn't being detected ("No Modem Attached") - trying to 'turn on' a 'non-existent' modem won't do anything except error.

Oops, I meant to post this in the bug report section.

Thanks for the replies everyone. Yes, since it fails to detect the modem…

rednet.open("left")

does not work.

I just did a quick test and this issue doesn't seem to exist in single player, unless I'm missing a step to replicate it.
I have not yet checked to see if this affects all turtles, or just my labelled one. I'll do some more testing in multiplayer once I get a chance.

I have been using the following code as a work-around to the issue

if not peripheral.isPresent("left") then
	inv.selectItem("") -- function from my own API that selects an empty inventory slot
	turtle.equipLeft()
	turtle.equipLeft()
	turtle.select(1)
end
...
local pos = vector.new(gps.locate())

However, I just learned that bad things can happen to CC (and probably other mods) if you close the server without issuing a "/stop" command. When I restart the server gracefully, the turtle boots up with a working wireless modem.