winscp does not start from commandline

If I start winscp3.exe (Version 3.8.2) in the following way:
and the password contains a % then WinSCP does not start.

You need to use %25 instead of simple %.
See https://winscp.net/eng/docs/session_url#special

Hey
There are more and more characters which can not used in commandline in the field password.
Why can I not use % or + in field password is this a problem with programming?
Can you create a version we can use all characters?
Thanks

The reason is that WinSCP treats the command line parameter as an URL address. So characters that need to be escaped in an URL needs to be escaped in command-line.

Is there a possibility that Winscp escapes the characters?

Edit 2021: The recent versions of WinSCP, you can use /username and /password command-line switches to provide credentials without URL-encoding:
https://winscp.net/eng/docs/commandline#username