The reason behind the problems, and how wide it could reach, is because of an incompatibility issue between the Logitech Control Center app and macOS Sierra. As mentioned by a poster on the Logitech forums, on the latest 3.9.4 software for LCC, the M705's forward and back buttons were reported as "not working," while scrolling was being problematic as well.
A separate report, posted on StackExchange, detailed a similar issue with Logitech's mice on macOS Sierra. The user described their mouse as having "soggy inertia" scrolling in native Apple apps, and "choppy" scrolling in third-party apps. Ultimately, they found that updating to macOS Sierra "wrecked scrolling" on the Logitech mouse.
The scrolling behaviour is erratic because I'm actually assaulted by two issues:The Logitech Control Center Mac app allows users to customize the features of their Logitech accessories -- mainly mice and keyboards -- along with basic features like notifications for low battery life and when each device has a firmware update. Its incompatibility with Sierra appears to be the source of the problem users are describing online. Unfortunately, Logitech has confirmed that "LCC is not available on Mac Sierra," and that "there is no release date known" for when it might launch.
In native macOS applications, like Apple Calendar, there is an ”inertia-ish” effect that slows down the scroll and introduces some sort of acceleration-like movement akin to the worst nightmares from Windows 10.
In third-party applications, like Google Chrome, the scrolling is quite fast but not fluid; it's choppy and non-linear with sudden jumps and stops. Because of this, it feels like the computer is laggy when scrolling a page, but it's probably due to the way the software scrolls.
Hello all!The same user who mentioned "wrecked scrolling" did appear to find some solutions to the problem, although they noted that everything was just "temporary band-aid tweaks" in the face of Logitech's lack of support. The user noted that messing around with the scroll and zoom settings in System Preferences > Mouse could help slightly, as well as checking out System Preferences > Logitech Control Center > Vertical Scrolling.
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As of right now, LCC is not available on Mac Sierra. And there is no release date known.
Once it is available, it will be posted.
Thank you all.
Update: Logitech has released a new version of its Logitech Control Center that's designed for macOS Sierra.