I have a mechanical drill contraption that just moves one space back and forth to mine the blocks from the andesite generator. Chests and a Portable Storage Interface are both glued to the contraption and work properly. However, some of the mined blocks seem to not go into the contraption inventory and just pop out into the world. I know the contraption works because when the storage interfaces connect, some of the blocks that did make it into the contraption inventory are transferred to my static inventory setup. I just don't get why only some of the blocks end up in the inventory and the rest just pop out into the world.

I've included some screenshots of my setup in the hopes that my problem will be easier to understand. The way my contraption is setup, the mechanical drills work at the same time that the portable storage interfaces are connected. My only theory is that while the portable storage interfaces are connected, whatever blocks the drills mine aren't able to go into the inventory at the same time. Can someone confirm this before I go completely redesigning my build?

Setup Screenshots & Explanations:

1. Left Drill Contraption after I cleaned up all the drops - https://imgur.com/B2Ha6Jl
2. Left Contraption after a few rounds of mining blocks (notice the dropped granite blocks in the lower middle of the screenshot, between the belt, scaffolding, and blackstone) - https://imgur.com/uDesqxk
3. Right Contraption with lots of dropped blocks - https://imgur.com/Q5dUmVr
4. Static Storage Connection to show that items are being pulled out of the portable storage interface, and this step isn't any choke point - https://imgur.com/6uZXCJT

Any help and suggestions are greatly appreciated. Thank you!

I figured out that it was the problem I explained above. When the Portable storage interface is active, the contraption inventory does not seem to actively accept more items. So, in my situation, since the mechanical drills were technically breaking blocks at the same time that the portable storage interface was transferring items, at least half of those blocks were just being dropped into the world rather than going into the contraption inventory. I don't know if this is intentional, but I just reorganized my setup so that the storage interface only activates when the drills are in a position where they can't break any blocks.