Inserter Randomly Stops Working

[Adeon Hawkwood]

I was attempting to design and debug a factory and encountered a weird thing with an inserter that I don't know how to fix. To explain, I found that loading my cassemblers directly from the line was insufficient since the factory would run out of resources in the time the inserter took to collect them from the belt, so I setup a system where two inserters would load a buffer chest which would then be used to feed the assembler itself.

The problem is is the inserter circled in red. Once the buffer chest hits the storage limit (I've tried several different storage limits) that inserter stops working. It just sits there with the grabber open (as shown in the image) but never collects any items from the belt. I've verified that I'm not short on power and experimented with a few different things such as using a fast inserter instead of a stack inserter but the problem remains the same. That inserter, and only that inserter, stops working. Does anyone have any suggestions on what might be causing this? I'm thinking maybe it's a belt speed issue, but the others that are working the same way are fine so I'm not sure why that one would go wierd, and in particular why it would fill the chest once before going wonky.

[Loewchen]

Post the save.

[Adeon Hawkwood]

Here you go. If you flip the power switch near the roboports the belts will get loaded and the inserter should jam after a minute or so (hopefully, it happens to me every time but you never know with these things).

As a side note, this appears to be a very specific timing related issue. I tried an alternate setup where I had the belts pre-loaded with a break in the beltand filling in the break was my go command and when I did it that way the inserter worked just fine. Sorry, I probably should have posted this in the bugs forum but when I made the post last night I thought it was user error .

[Loewchen]

The inserting is still working, it just can not grab from this position in time when the items move at full speed, avoid this arrangement of inserter and underground belt if this is an issue for you, but since it fixes itself once the items slow down or space out this should not be necessary.

[Avezo]

I'm just randomly here, but stack inserter should be able to grab anything from blue belt in any position to my knowledge. Actually, any inserter should except burner, yellow and long one.

[The Eriksonn]

You dont just have a normal belt but an underground belt, that means only 50% of the belt is visible to the inserter and thus 50% of the timelimit.
its the same if you had a belt 2x the speed of blue belt and try to grab from that...