My scenario
Windows with ntfs → create a file named Man.jpg
synced with my
xubuntu with ext4 → Man.jpg gets synced
change the name of Man.jpg to man.jpg on my windows pc
i have now Man.jpg and man.jpg on my xubuntu, thats not really synced right ? 
In short, on the Windows side we detect man.jpg as a new file, but when checking for Man.jpg we can see that it still exists (because case insensitive). Hence we interpret it as a new file and not a rename. It’s a bug.
To fix this, rename the file to foo.jpg (or anything that is not a case-only variant on man.jpg), make sure that change is scanned and synced, then rename it back.
Ok, i try it, thanks calmh.
Jakob, change your picture, man.
Too damn serious.
