can't login to linked pages

You can login to crabgrass normally if you go to https://we.riseup.net, but if you are passed a link to a page that requires that you login first, then it is not possible to login. You get the login/password boxes, but your password does not work.

For example, if you are logged out and you try to visit https://we.riseup.net/friendlygeek/cs+396459