That should indeed be a way to work around the bug. You could test it out with dirt first to be certain.
As I said before it works with small number of items. As you are a high staff member I assumed you destroyed a sign with at least 500 items in it. I don't know though...
When you tried this, what item did you have in your offhand: the same you were retrieving from the sign, or a different one? With a different item, it worked for me (no bug), though I tested it only with amounts slightly bigger than a full inventory (just a few stacks more). Maybe the offhand behaves as a blackhole only if it contains the same item you are retrieving?
Uhm... it never happened to me (while having something in my offhand), despite I don't usually wear armor when I manage my shop
Lol what alt has thousands of command blocks? *Clar, imaginex, jamie, andrew you're not allowed to answer this*
We'll be looking into a fix for this finally once we roll out 1.11 publicly and fix all current 1.11 issues/plugins.
Bumping for @JamieSinn - please document everything related to this in a github issue on our Essentials repo so we have it stored somewhere for a future fix.
