I had an odd issue with the Mekanism logistical system and the new storage controller of Storage Drawers.
Full story of the incident:
thephoenixlodge/Regrowth-Stuff#18

I was later able to reproduce it in SSP, although not reliably (includes stacktrace):
jaquadro/StorageDrawers#52

No way this can me on my end - there's some form of faulty ISidedInventory implementation going on by the Storage Drawers. I simply iterate over the list of slots given by getAccessibleSlotsFromSide(), the crash is basically saying that the list returned contains missing element(s).

Mekanism makes an assumption that all slot numbers are less than the length of the slot array. While I have not encountered an issue with other transport systems I've tested, I feel like I'm the only mod challenging that assumption, and so I've changed the behavior on my end.