Pictures say more than a thousand words, so I'm attaching two simple gifs that illustrate the issue as i'm experiencing it:
Ghost-placing straight rails through forests seems to function normally:
![Image](https://forums.factorio.com/images/ext/28fb8d81b2b71c8457fbdd9bde99850a.gif)
Ghost placing rails with curved segments through forests does not, it clears trees obstructing the straight elements and places these, but all trees blocking the curved segments are left standing:
![Image](https://forums.factorio.com/images/ext/f76177dd5e1faf017742b7ab09f6b3f5.gif)
Tried asking others to reproduce, but they do not seem to experience the same behaviour, so I'm not entirely sure if this is some bizarre local flop on my end.
Creative mode mod is installed, but not activated. No other mods at all, so the game should be completely vanilla.