Typewriter build step 312. Red arrows point to two upraised open connectors. What part of the segment snaps into them?
If snapped to the rod outside of the two gray mid-rod spacer pieces (step 309), the resulting gap exceeds that of the two 90 degrees vertical rods that the connector pieces connect to.
The image is from https://lego.brickinstructions.com/en/lego_instructions/set/21327/Typewriter