First I noticed I was able to place an Underground Duct one tile off center and the pipes would still connect, then I started to wonder if it was possible to connect two Underground Ducts. Sometimes it "seems" to work but usually it removes one of the offending pipes - however with this configuration in the screenshot I was able to get two pipes connected.

If you're wondering about the behavior, it seems that it distributes the fluid evenly through both connected pipes but doesn't cut the flow rate in half if only one pipe is connected off center.

The expected behavior is to have ducts require perfect alignment - that would solve both problems.

https://steamuserimages-a.akamaihd.net/ugc/1701783652698397991/FC7882A899FC4191F2C634804660EB3DC0BE8559/