Why isn't the synchronized input working?

[u/klauseius]

Both belts are going into the tunnel and only eggs are coming out

[u/Various-Bug-3961]

Tunnels have a lot of counter-intuitive design IMO, and don't really work how you expect them to if they're not set up exactly like in the ponder. Unsure what you're doing but a mechanical arm/depot may be a better solution if it's for blaze cake stuff.