Updating Logitech Options to version 6.70.1055 (Aug 31) made smooth scrolling in Windows 10 apps (such as Edge) extremely unresponsive. Version 6.70.1197 (Sep 14) does not address this issue.
If you have the same problem, please help raise awareness on the Logitech Community thread.
Meanwhile, you can uninstall the new version and reinstall version 6.62.210 from Logitech’s website: https://download01.logi.com/web/ftp/pub/techsupport/options/Options_6.62.210.exe
To prevent Logitech Options from annoying you with update notifications, click its “MORE” button, go to Software and uncheck “Automatically check for updates“.
Update Feb 1, 2019
Someone from Logitech Escalation Desk emailed me and sent me a new MX Master. But the problem persists even on the new unit!