It appears to have treated the Turkish letter İ as equivalent to the Latin letter I, and simplified the link per [[Wikipedia:AutoWikiBrowser/General_fixes#Simplify_links_(SimplifyLinks)]]

You can duplicate this with [[User:GoingBatty/sandbox]] using AWB 6.2.0.0 SVN 12469

The reason is that to correctly simplify both [[Dog|dog]] and [[dog|dog]] i.e. allowing that first letter of link may be upper or lower case, we turn first letter of both parts of link to lower case. That means that both İ and I become i so are considered the same, which is wrong.

rev 12500 SimplifyLinks: fix handling of diacritics on page's first letter

In T285941#7190949, @Rjwilmsi wrote:

The reason is that to correctly simplify both [[Dog|dog]] and [[dog|dog]] i.e. allowing that first letter of link may be upper or lower case, we turn first letter of both parts of link to lower case. That means that both İ and I become i so are considered the same, which is wrong.

rev 12500 SimplifyLinks: fix handling of diacritics on page's first letter

I get the conflation of uppercase "I" and lowercase "i". That's correct, and that is a helpful fix: simplifies markup, and causes no change to the displayed text or the link target

But something is going wrong here, when the Turkish uppercase letter is converted to the unaccented Latin uppercase letter.

As far as I remember this problem was not only connected to AWB but it was more general. Even when I was searching for the Turkish letter, I was getting the Latin "I" too.