In my AE Networt setup, I have some Storage Drawers set up as external storage. I wanted to move my 52k Emerald Dust from the (one) Compacting Drawer to the ME system's internal storage. With the magnet card in my Wireless Crafting Terminal (WCT), I just pickaxed the Compacting Drawer and have the WCT collect the items back into the ME network. At least, that was the idea. What actually happend is that ALL items got deleted. They dropped from the drawer as expected (causing a short time of extreme lag as one would expect) but then, when they disappeared (as expected when using the WCT's magnet card function), the items were just gone. I tried with some single instances of Emerald Dust that I still had in my inventory, drop them on ground, they got added to the ME system as expected.

Maybe of interest: Inserting Items to the Storage Drawer system has higher priority than adding them to the ME Drives. So, if this is some race of AE not noticing fast enough, that the drawer was gone in addition with some other bug like the drawer system to accepting the items in spite not being able to add them anywhere anymore, this might be the resason.

Found the report #246, but that seems to be a different issue.

FTB Continuum 1.4.1, Forge 2730, AE rv5-stable-11, Wireless Crafting Terminal 3.9.67

Storage drawers are innocent, I reproduced it using a vanilla chest:

Setup:

Creative Energy Source
ME Controller
ME Security Terminal
ME Wireless Access Point
ME Crafting Terminal
ME Drive + (extra storage) Cell
ME Storage Bus, Priority 2 (ME Drive stayed on default 0)
Vanilla Chest connected to ME Storage Bus with 27 Stacks of highly valuable Creative Cheated Diamonds
Wireless Crafting Terminal + Magnet Card, configured to accept Diamonds and activated

Experiment:
Break the Chest

Expected behavior:
The items drop and get (instantly or with a short delay) added to the Storage Cell withhin the ME Drive.

Observed behavior:
The items drop and get instantly deleted.

Changed Setup:
Disallow adding Diamonds for the Magnet Card.

Experiment Step 1:
Break the Chest.

Expected and observed behavior:
The items drop to the ground.

Experiement Step 2:
Reconfigure Magnet Card to Add Diamonds.

Expected and observed behavior:
The items get added to the Storage Cell withhin the ME Drive.

Third experiment:
Put Wireless Crafting Terminal aside (in some random chest)
Place an ME Annihilation Plane, so that it faces the block occupied by the Chest and connect it to the me system.

Expected behavior:
The Chest will be broken down and added to the ME System.
The Diamonds will drop and at least a few of them touching the Annihilation Plane will be added to the ME System

Observed behavior:
The Chest will be added to the Storage Cell.
The Diamonds drop and get deleted.