Project icon files (the generic icon+color) are missing from several projects.
They have been present on 22nd February and disappeared after that, more exact time unknown ATM.
I timeline of those projects it says:
<username> set the image for <projectname> to Unknown Object (File).
All active goals should have the project icon orange flag.
Most of active timelines should have either own icon or green calendar.
According to @mmodell on IRC, at least one of the files is missing from db completely.