Thanks for telling me that! I realized that I can make the same mistakes locally with comparable frequency. Perhaps it's just that I feel annoyed when I have to backspace with latency.
It predicts what the server will do with your input and displays the result (with an underline) until the server responds. This means typing is always at local speed even if the network is being flaky.
ssh doesn't see the keystroke until it's fully formed by your OS and/or window manager, so there can be no latency to the release of shift.