The GUI of the Assembler is bugged, it doesnt accept patterns, and in the upgrade slots you can put whatever you want

and the 3x3 acts like a pattern terminal in the way that you can set "ghost items" for the patterns

fluid assembler only accept fluid pattern (the dark blue one)

you get it by clicking the encode button on fluid pattern terminal

the normal crafting pattern won't be accepted

other issues will be fixed later

fixed in 2.4.33 https://github.com/GlodBlock/AE2FluidCraft-Rework/releases/tag/2.4.33-r

<3 Thank You for that