I'm a CJK user.
Note that there is nothing before “git” when I press “↑” on keyboard
I keep press “↑” on keyboard to to get out another history command
“vagrant ssh”,then I press “↓” on keyboard to get“git” back.
You will see that there is a additional “v” fom “vagrant” before “git”
But it's actually a “git” there ,not “vgit”. the "v" character is just like a ghost
here is a screen record,I'm Using windows 10 (64 bit), with chinese language enabled, same issue on windows 7 (64 bit),with a clean install of cmder 1.3.2

Open: Cmder\vendor\clink.lua
https://github.com/cmderdev/cmder/blob/master/vendor/clink.lua#L44
Change:
if env == nil then
lambda = "$"
else
lambda = "("..env..") $"
end
@Kisesy It works..
Why don't provide any settings to change this prompt ....
add chcp utf-8
see https://github.com/cmderdev/cmder/issues/1339#issuecomment-293768557
@clijiac it‘s not a utf-8 issue
I‘ve tried
run chcp 65001 won't work. and some programs such as vagrant won't work in utf-8 code page in Chinese env
change the prompt from λ to $ here work the best and cost the least.
I have met exactly the same issue. Following @Kisesy 's advice, it works. Go to where cmder is installed, e.g., D:Program Files, the clink.lua file is in vendor sub-directory.
I have facing the same issue. I tested it on my Windows10 laptop, and this issue appear only when I add
chcp utf-8
to Cmder->Setting->environment

And I have also have downloaded the ConEmu to power my guess.
This issue doesn't appear in ConEmu.
It may be the mistake when calculating the length of character λ that lead to this issue.
This issue still persists. Solution for the latest release of cmder (version 1.3.8) can be found here.
This issue has been automatically marked as stale because it has not had recent activity. It will be closed in a week if no further activity occurs. Thank you for your contribution.
Most helpful comment
Open:
Cmder\vendor\clink.luahttps://github.com/cmderdev/cmder/blob/master/vendor/clink.lua#L44
Change: