I tried to find proof of what I was saying and
this is the best that I found. I know the video is quite old but I don't believe Valve has changed the Sandvich retrieval mechanics since then.
At 0: 36 you see the player who recorded the video throws his Sandvich. If you keep track of his Sandvich for the next few seconds, you'll see that he walks over it at 0:55 and it doesn't disappear.
Also, at 0:40 you'll see a RED heavy throwing his Sandvich down on the ground. You see him walk over it at 0:49 and it doesn't disappear at that moment either.
Honestly, I mess around on servers a lot. I threw Sandviches around all the time and as soon as I noticed that I could pick up the Sandvich while using the plugin, I knew something was wrong.