Invite a colleague at Anna.Kowalska@example.com and the link in the email led nowhere: the page answered with a plain 404, with no explanation and nothing to do next. The same invitation to anna.kowalska@example.com worked. Nothing on screen suggested that the capital letters were the difference, so the usual conclusion was that the invitation had expired — and a second one, sent the same way, failed in exactly the same manner.
An email address does not distinguish capital letters, and the platform now treats it that way from end to end: when the invitation is created, when the link is opened, and when the invitation is finally accepted. An address written in any combination of upper and lower case reaches the person it was meant for.
The second half of the fix is what happens when a link really has stopped working. Instead of the bare 404, the page now says Invite not found or expired, and explains: The invite you are looking for is either expired or does not exist. Please contact the team owner to renew the invite. That message was always intended for this situation; until now the page never reached it.
Invitations already sent are unaffected. Nothing was rewritten in existing invitations, and a link that worked yesterday works today.