I have had it too...I thought it happened when my game froze and maybe I clicked "ok"..too fast or 2 times maybe..and confused the rock.. :)
Maybe some genius staff can enlighten us....Cos now am curious...lol
I got this message after helping with a tower, too.. is there a certain level of help you must provide to earn img? Maybe i didn't contribute enough resources to the project.
Tower projects don't give iMG. They give towers! =)
In my experience, the rock says that when something in the game tries to trigger an event (iMG from a project, new quest, etc.) but there isn't the right information about what it is. When you guys have been helping with towers but not there at the end, are you still getting a "Project Complete" message? It could be that there's no specific code for a case where you get that message from someone else's project, aren't there when it finishes, and get no reward with it. The only time I've helped with someone else's tower I finished the level, so I was the one who triggered the "Project Complete".
Edit to add: if that's the case, it is certainly a bug, albeit a fairly minor one.
I just loaded a new OS, and logged in...got all the 'update menus' for the new interface, and then got a TON of these messages...it's like it didn't remember that I've been in game lately.
b3achy, that will happen sometimes. Every once in a while, some things are stored on your computer (for example, whether or not you've seen the alerts telling you that things are new). So if you get a new computer or load a new OS, the game info that says "this person has seen this thing" isn't there any more. The same will happen if you clear the flash cache.