We have one card that we are not able to access from the desktop app. When we click on it, we get a card not found error. We can access it like normal from the phone app. This is true for multiple people within our organization and from multiple different computers.
The Trello Statuspage lists this issue as resolved as of May 26, but it is definitely not resolved for us. Luckily it is just one card for us (so far), but this issue also only just started yesterday.