Switch turns and regular turns are not the same size, which makes it impossible to connect rail to it the same way.

Length: 16
Curve: 45deg
https://i.imgur.com/gzBGUuT.png

Length: 20
Curve: 45deg
https://i.imgur.com/ULIQKja.png

Length: 16
Curve: 90deg
https://i.imgur.com/d1OghzE.png

Especially the 45deg switch turns are broken. They don't line up to any normal-mode placed tracks, while the regular 45deg turns do line up with normal-placed tracks (if you discount overlap).
Shouldn't you be able to place everything without smooth mode anyway?

This is not intuitive, and should be changed in my opinion.

It's a known bug that the switch size is off by one relative to the turns. Decrement the size by one and you'll be fine.