I found the answer to a problem with similar symptoms.
I’ll include it here for someone who finds this page looking for an answer, as I did.
In my case, the cursor didn’t move, or show my typing onscreen.
However, it actually executed the command (if I pressed Enter), even though it looked like I didn’t type anything in!
The solution was to type reset < Enter >
Turns out it can be an issue for any shell program (cmd, git bash, etc), not necessarily just a Git Bash issue.
It looks like Ctrl-C or Ctrl-Z can occasionally result in the terminal not echoing commands to the screen, depending on what process was running at the time it was killed.
reset restores it.
I found the solution, and the explanation why, at https://askubuntu.com/a/172747/636571