I hear audio clicks during playback in FCP - after I moved to another place in the timeline.
I don't hear them when I use other outputs, so I guess it must be a Decklink issue.
What could be the cause?
I haven't come across any problems like this with Final Cut Pro before. I would suggest trying with different footage and settings and see if the problem remains. If it does, it would be worth checking if reverting to older drivers makes any difference.
If you're then still seeing the same problems please contact support since they will be better able to to try and reproduce the issue and suggest what could be causing the problem. You can contact support using the numbers on the page here, or using the support request form on the product's support page.
I changed to another system disk (an HD instead of an SSD) and now the problem vanished, so that makes it not a Decklink issue, unless there is a reason why the Decklink would behave differently with a SSD instead of a HD.
Could a SSD be too fast for some action related to AV output?
(OK, I know this sounds ridiculous but... well, you never know)