I have also been having an issue logging into User Voice for the past month or so. It would tell me my password was invalid. I have logged into it several times before and voted, even submitted my own topics there. This solution worked for me too technically although I did not have to log back in which is weird. The links in the feedback tab you mentioned let me view User Voice again.
Hopefully that continues and the next time it is linked on the forums I can go there without logging in. Either that or I will use this workaround then too. I made sure to click the "stay signed in" link, so fingers crossed. Thanks for the tip.