For some people this is better after the update to 1.2.8. Aparently the software team is working on improving matters further in a next update (though I can't seem that statement on the forum at the moment). There is some discussion about this issue here:
This is discussed here, it appears that some of the camera modules are defective in some way:
If there are any other issues that you wonder whether others are also experiencing, check out the common issues topic or the bugs list.
Fairphone support has had some major issues and are still working to recover. Unfortunately it's not unheard of that support requests have gone unanswered for months. Depending on how you filed your support ticket the first time, you could consider opening a support request under the repairs category for the camera, as this seems to have worked for some people in the topic linked above.