Example: Since recently it's no longer possible to scroll down in
the coach's speech bubble to view the best move, although I have enabled
the ' Show Best Move' option in the settings.
possible.
Developers arnd projects are happening all the time with code updates (bug fixes, optimizations, new code, new projects) being pushed out sometimes multiple times a day.
There are also changes that are only in beta, some that go out to a subset of members to get feedback and other usage data, etc. major releases usually get a news release or are mentioned in the monthly site updates.
Due to the amount of ongoing work, and different groups that get code updates, it's not something that is easily communicated or digestible.
why doesn't chess.com inform about its updates and resulting changes?
Example: Since recently it's no longer possible to scroll down in
the coach's speech bubble to view the best move, although I have enabled
the ' Show Best Move' option in the settings.
Even support is not informed and constantly claims that this should be
possible.