As the title says, fast inserters will always point south when placed and you have to manually flip them to point north, yellow inserters don't have the same problem with their east/west orientation. If this is intentional you can close the thread but it's annoying af

There's a multidirectionality research that is in dark green science, though I'm moving it to light green science in the next update. The ability to flip them to be correct is a bug, I hadn't thought of that.

I'm almost at the point of unlocking it so it's not that big of an issue, but just to clarify, you're saying they're meant to point south only?
On another note, the furnace stack being a single building is something I never thought I needed in Factorio until I played this, there are quite a few great ideas you put into the mod

They're meant to only point south, but hopefully moving multidirectionality to light green science won't make it too bad. Maybe I could make them like a regular inserter though? I'm not too sure but glad for the feedback!

Glad you like the furnace stack!