CTRL+D CTRL+K bug because of case insensitivity/sensitivity mix

Create a new file with the text:
TITLE
title
title
TITLE

Now select "title" and CTRL+D to select the next one until you select the first "TITLE" and try to deselect it with CTRL+K. It will deselect the last "title" and keep the "TITLE".

It looks like it is case insensitive to select, but case sensitive to deselect. It does not find TITLE in the pile of items selected somehow.