Okay, so, there seems to be a slight issue with Multiplayer servers when using the Robosurgeon. You see, when other players try to use the machine after one another there are some serious issues with syncing. The Robosurgeon will start to spit the items back at the player, not put them into the player's body, create doubles based on what the first player had, and more. The problems do not persist as long as the machine is broken after each player uses it, but it's a rather large inconvenience.

Suggestion:

A way to fix this being to implement a second type of Robosurgeon specifically for use on other players (and even mobs, once more mobs can become Cyber). This way, one player would be able to edit another's cyberware without it conflicting as it does in the normal machine. It could also make for some rather interesting mob experiments, maybe even being able to remove limbs on a zombie, or put an Ender Jammer into an Enderman.

While the issue should still be resolved otherwise, that suggestion could still be added. As for a fix for now, perhaps making it so that each player has their own profile in the Robosurgeon so that they can edit themselves and one another without conflict?

(As a side note: I to have been noticing the issue with items and upgrades not appearing when you go to them specifically in the Cyberware menu of the Robosurgeon. I know others have been having this issue, and I can supply a full mod list if that would help you narrow down the problem whatsoever. Example: http://i.imgur.com/kMuxfsz.png)

A full mod list for the visual problem would be appreciated in helping me narrow it down.

The Robosurgeon issue seems odd, I'll see what I can do.

We are also having Sync issues
Here is our modpack, Hope it might help you narrow down stuff :)
(If I got the time ill try and see if I can do some troubleshooting myself)
http://pastebin.com/7QwpstLv

We also experience strange behaviour with the Surgeon, most of the time it wants to remove our arms or legs w/o us even fiddling with those parts.

Here's the full mod list for our end, versions included.
http://pastebin.com/NUNzEHFh

I do surely hope this helps you sort out any problems, thank you so much for your hard work.

Just did some quick spreadsheet'ing with all the three modlists. The script to count duplicates may have missed something due to slightly different names. But its something to work with atleast maybe

https://docs.google.com/spreadsheets/d/1GM3WQEEsfuKRZ-YbWCVTy00jDeG6N4B9ewVdJq4WykM/edit?usp=sharing

Range goes from 1 - 115, Green is Duplicate

For what it's worth, in the "Hypothermia" modpack the visually empty robosurgeon bug also occurs.
It's a bit of a smaller modpack so there's less mods that might interfere with it.

https://minecraft.curseforge.com/projects/hypothermia

If you open up the index everything shows up fine though.
http://i.imgur.com/ambBjqu.png