but I will ask some of the windows users if it is actually working for them

That would require "the windows users" to be running the script on Windows. But elsewhere you said:

But as several other people use this script some are also connecting to this linux server from windows and mac clients

That won't make a difference as the ssh client will be reading what they paste asynchronously and thus (on Windows) causing it to be echoed before the script has read that same data.