Assembling machine 2 not accepting lubricant

[Mink]

Hey,
I am playing on 0.13.8 and today I tried to automate the production of electric engine units.
Strangely, the assembling machine 2 does not accept lubricant-pipes from it's east or south side. However, if you attach the lubricant-pipes to the west or the nord side of the assembling machine, it works just fine. I guess that this is a bug and I hope that it has not yet been reported.
Two pictures showing the issue:

Assembling machine accepting lubricant

Factorio Assembling Machine 2 Bug (1).png (1.03 MiB) Viewed 1935 times

Assembling machine not accepting lubricant

Factorio Assembling Machine 2 Bug.png (811.39 KiB) Viewed 1935 times

[daniel34]

Inserting at least 1 of another ingredient will also insert lubricant into the assembler. It is not game-breaking as the assembler starts to produce as soon as enough ingredients are available.

But the fact that assemblers do not pre-fill with lubricant from east/south but do from west/north is a (minor) inconsistency.

[Rseding91]

You need to put items in the other recipe slots before the fluid flows in.

As an optimization the machine is asleep because it knows it can't do anything until the items are available for the recipe regardless of the fluid being present.

The reason it fills with fluid from some angles and not others is: the pipes move the fluid when they're left/top of the machine but the machine is responsible for pulling the fluid from the right/bottom except it's inactive in this instance. It's just a quirk of how fluid flows in Factorio.