fish --no-config -C 'fish --no-config --init-command=fish_vi_key_bindings'
Type any random text: abcd
Hit escape to return to normal mode.
Press 'r' to enter replace and type 'e' to replace the last character 'd' with 'e'
The result is: 'abed' instead of 'abce' (the cursor is shifted one place as well)
Replacing any other character is fine.
Tested with 5575272 but I believe all 4.x versions show this behavior.
3.x works fine.