Assemblers need to clean their inventories
Not sure how to classify this, on one hand it looks like a bug but looking at the code shows that it's not actually doing push requests, therefore I'm adding it as a suggestion.
Assembler never does push requests for its input inventory when in assemble mode, and never does push requests for its output inventory when in disassemble mode.
That means the input and ouput inventories eventually get clogged by cancelled queue items or simply refinery placing ingots there because assembler is closer on the path or something (which I did test and does happen, see last attachment)
One quick-ish way to cause the clogging to happen:
1. A survival world with all realistic inventory and speed settings.
2. Have an assembler, power source and cargo container.
3. Add to the container 10k of: silicon, iron, silver, gold, cobalt.
4. In the inventory, drag the silicon to the assembler's input to fill it.
5. Drag 25 silicon from the assembler back to the container.
6. Try to assemble a gravity generator component.