That's a deliberate change on PuTTY site:
https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/cmdline-pw-local-prompt.html
Basically, it should have never worked.

Hello! There is one problem with PuTTY since version 0.78.
If the server has configured authorization by a key with a passphrase, then when opening a PuTTY session, a passphrase is requested from WinSCP.
"Preferences > Integration > Applications > Remember session password and pass it to PuTTY (SSH)" is enabled.
In PuTTY version 0.77 it works, and in 0.78 and 0.79 it stopped working.