I have two saved sessions - s1 and s2. The bug shows with s2, but not s1.
1) I connect with s1, and pres CTRL+P, putty opens and goes automatically through the login process and shows me a working shell prompt. Works as expected.
2) I connect with s2, and pres CTRL+P, putty opens, but it prompts with "login as:". I have to manually enter the username, and then it logs me in and shows me the shell prompt (UNdesired behaviour).
3) (workaround) I open the login window, go to Saved sessions, select s2 and click Edit. Then I press the Login button. Putty opens and logs me in right to the shell prompt without asking me for username (desired behaviour). What I also notice is that the connection Tab name is now "myusername@ipaddress" instead of "s2".
I am pretty sure it is not about settings, because I compared s1 and s2 and except for the IP they are exactly the same. I also checked with colleagues using s1 and s2 and they don't have the issue.
Protocol used is SCP; Server is AIX 6.1
Windows 7, 64bit; WinSCP 5.1.3 (but also with previous versions)