Yep, that's how they work.

And this is intended behavior?
Assemblers obviously have an internal rotation, even when not having any fluid ports.
https://i.imgur.com/VmVbfzW.mp4

We should be able to manipulate this property the obvious way (R), even if the fluid port isn't present. We can so ...

It is impossible to rotate an assembler before a fluid recipe has been selected. When a pipe with wrong fluid is present above the assembler, this will prevent selecting a recipe and rotating, making it impossible to rotate it to the correct the orientation.

Steps to reproduce:
1. Create setup in ...

Changing the desktop scaling to 100% reduces the problem, but does NOT totally remove the issue. See screenshot

And yes, it is only a (very) minor issue, totaling a total of a 2 second annoyance, I simply missed the existence of this subforum.

0. On a 3000x2000px screen
1. Beforehand, change Factorio to Windowed mode.
2. Open Factorio by right clicking the Steam icon in the taskbar > Factorio
3. Factorio starts and extends slightly past my screen at both top and bottom (see screenshot)

Expected behavior:
Game window fits entirely inside ...