Preliminary Information:
Minecraft Version: 1.12.2
Forge Version: forge-1.12.2-14.23.5.2768
Practical Logistics version: 3.0.4
Industrial Foregoing version: 1.11.5

When attaching an inventory reader to a black hole controller via data cable and node, the inventory reader intermittently reads the item properly, reads the correct count but instead as 'air', or starts filling up with numerous 'air' counts.

For example, I have black hole controllers storing cobblestone and dirt. Both are setup identically.

The cobblestone black hole controller's inventory reader shows this:

The dirt black hole controller's inventory reader displays this:

Despite identical setups, you can see that these two devices behave differently, with one working and one not. Both readers have had the same 'air' anomaly previously, but after some tinkering I had got them working. However, once the chunks were unloaded (I left the server) the readers went back to reading in massive amounts of 'air'.

The inventory reader still works correctly with chests, etc. So I believe it's just a compatibility issue with the black hole controller, probably due to the fact it actually holds 9 of the black hole units that then hold the items themselves:

Thanks for your time, I hope I've provided all the information necessary. Let me know if anything else is required. :)

Fixed in dev