When I convert a blueprint that includes space scaffolding and place the blueprint down, only the scaffolding is getting put down, but not the entities that would go on top of it.

That's weird converted ghosts should be placable in space regardless whether or not the BP has scaffolding or not, what entitys are you trying to place?

Things like space pipes. Copy some pipes (without scaffolding) to get the blueprint in your hand, then click on the 'make blueprint water placable' button (wonder if this button needs a new label since it could be 'space placable' too haha). Then attempt to place the converted blueprint down

https://streamable.com/idpiho For how I was attempting to use this mod in space.

That blueprint hasn't been converted (you can see that by looking at the blueprints required items they don't have the ghost on water icon), don't know why it didn't convert tough, it should have converted. I guess you could just try converting it again, maybe try another BP or with your inventory closed or using the keyboard shortcut (control + W by default), really don't know why it didn't convert it should convert whatever in your hand as long as it's in your inventory which this BP clearly was.

Unfortunately, it is converted. It converts using the button or the keybind. It doesn't work. Here's another video. Here, you see me look at a blueprint that is not converted. I then convert it by clicking the hotbar button, then confirming that the entities in the blueprint have the ghost icon. I place the BP down, but it is partial. Then, I unconvert it, use the keybind as you suggested, still no success.

https://streamable.com/dt3n2q

Don't really know why it dosn't work, probably related to one of your installed mods or somthing.
Can you send me your save file, just go to %appdata%/factorio/saves in windows explorer, upload it somewhere and send me the link, that will allow me to debug this issue.

Sure, https://drive.google.com/file/d/15vUrNOvNq-GTTydQlq0op4P0PN7HesYX/view?usp=sharing

You are right, I started a new game and loaded only the base Space Exploration (+ AAI), K2, and Editor Extensions, and it worked.

After disabling and enabling mods in groups, I was able to single out Balanced Waterfill is the mod breaking the behavior of this mod. Are you able to make compatibility between the two?

https://mods.factorio.com/mod/balanced-waterfill

Maybe I have to look and see what that mod does to make it incompatible.