As the title says, disconnection issues, the only exception this is if I'm in Map Editor or in a room with 5~10 people, which is a pain when trying for firsts.

I got a standalone (Forgot which) and that solved the issue temporarily as now, I DC after 2~5 minutes

Sounds like your PC is unable to process large amounts of mice if Map Editor or small, private rooms are safe.
Specs?

Windows 7 able to run 3 lag intensive Unity games at the same time

Hmmm.
Alright; well to be honest I've experienced this as well on my PC. I could run Terraria or Left 4 Dead but TFM lagged so hard I couldn't stand to play. Sadly, I never found a solution to the issue, short of the issue being somehting in the game's coding.

And now there is an added bonus, glitching out, when this happens, people fall off the map and don't die, trampolines and lava to nothing and if you were moving when this happened, you kept on moving and only I can see visible control