Placing an Aqueduct next to a functioning Screw Pump will not cause the Aqueduct to spawn fake source blocks
https://i.imgur.com/MiCTTQ1.png

i feel i've tested this one a bit too often now to be unsure about this
the problem is that aqueducts only accept water sources, and that means the block on top of the screwpump. This is actually specialcased, when a screwpump source is detected it will basicly delegate the check to the screwpump input. In this case it looks like there's a 1 block gap between each screwpump, so the input on the screwpump is flowing water, which is not a valid input for an aqueduct to prevent exploits.

You can fix this by putting aqueducts on the one-block stretch between each screwpump like so

Okay fantastic that did work! Thank you so much and sorry for assuming it was a bug xD

no prob, i get it quite often and it mostly happens because aqueducts are a bit stricter than screwpumps for easier code and to prevent exploits, so it looks like it should work but it doesn't. i feel like i should probably document it in the book sometime